What shocks me is the price ($5.50) for an all you can eat buffet.
That equates to £3.40 in the UK, which, here, would barely buy you a portion of rice from a Chinese takeaway.
I think there must be some sort of specal tax in Ireland on all starchy food that is not potatoes. 
Ask for a bucket. Avoid the ‘wafer thin’ mints.
With eggs on top, and double pate.
Heavy sweet (sugary) sauces and breading are very common fill you up items.
Some that I go to have clams on the 1/2 shell, I think they might go to the beach and get them themselves, but anyway they go for $2.99 a doz. at the absolute lowest price of the year at a fish market. I usually stock up on a good dozen or 2.
Shrimp also is fairly expensive - so stock up here (but watch out for breaded shrimplings).
Take soda only if included in the price
I have had the same though at you in the OP, Namely - at 1st I figure I’m getting a great deal "all this food for around $5.50, then I think “hey how can these guys make money giving you that much food”, then you think “hey these SOB’s are making money off me - I can’t allow that”
Shoot, I remember when Taco Bell had 50 cent tacos/burritos. Those were the days. My friends and I, after a full day of highschool, would drive up there with 20 dollars and we would get an ungodly amount of tacos and burritos. The whole next week, I’d be eating tacos and burritos.
Unfortunately they raised their prices and my interest decreased.
The good old days…Sigh
You should check to see if there’s a Dragon Sea Buffet in your area. It’s expensive, but it has lobster, duck, prime rib, and a ton of other food (including sushi)!
Also, if you are just looking to get your moneys worth, why don’t you eat as much as you can and then go back up for another plate. Stack it high and leave.
Get the shrimps and the beef. Avoid all rice, noodles, and vegetables - especially the rice! It’s the rice’s fault that you get hungry an hour after you chow down, have ya ever cooked rice? It’s all puffed-up water starch nuggets.
Think of it like this… if you took all those little slices of steak and tied them together, how many would it take to make a steak sized slab? or even a burger?
Quite so. Avoid the rice, the bread, and anything breaded. Stay clear of the salad; that’s incredibly cheap.
Tank up on the shrimp and oysters.
Then again, I’ve gotta add my voice to the others – any time I can eat out for five and a half bucks… and eat anything I want… and the selection is good… and I leave feeling full… and I really enjoyed the food… hey, I got the better end of the deal, and who cares how much money the restaurant made?
Ah, if this is the nub, then everybody happy. The buffet obviously loses money on the big eaters and makes it on the folks who eat only the spicy string beans over rice. The idea is that on the average they make a buck or two on each buffet they sell.
From that perspective, the OPer is probably already more than breaking even, and is sure to do so after all the advice on this thread. And, the effect of one guy is unlikely to materially affect the profits of the restaurant, so the bleeding hearts and the restaurant owners need not feel cencerned about the OPer’s behavior. There’re no way he eat more than $10 worth, unless he’s elmwood’d friend, so he just costs them the profits on 5 of the regular eaters.
The stuff to really avoid is the appetizers: greasy, bready, and cheap.
I used to eat the more expensive stuff, but then I realized that I would just be paying more to doctors due to the long term health consequences, so now I try to take more vegetables and rice and tofu.
I still pig out at the buffet, so the $6 (+$1 tip) usually means I don’t need to eat the rest of the day anyway. Great deal if you look at it that way.
Ever notice how these all you can eat buffets bring out the “wide bodies”?
Amusement parks have those signs saying if you’re taller than this mark, you are too old/big for this ride.
Buffet restaurants could use the same principle. Build the turnstiles say 30 inches. If you’re wider than that, we don’t want you grazing here.
To clarify, so as not to be thought a jerk, I bear them no ill will. I mean, they’ve served me well over the years and their Ancient Chinese Cheesy Potatoes are without peer. I just want to feel that I’ve actually eaten $5.50 worth of their food at least once. Right now, as per your advice, I’ve set my aim squarely on the shrimp, oysters, crayfish (maybe) and lots of free refills on soda.
P.S. I’ll leave a nice healthy tip to offset any profits of theirs I may take away.
Just make sure your soda drinking doesn’t interfere with the amount of food you can eat. Also, make sure to get a refill last thing before you leave, so as to leave a big ol’ full cup of soda that they have to pour down the drain. 
Novus
Actually, the soda is really cheap to them. That’s why the profit margin is so high.
Ya know I wasn’t aware ancient China had either cheese or potatoes … .
Where is this “Chinese restaurant” … Wisconsin?
I don’t get it. Instead of just eating what you would want to eat you will eat what costs them more? And you feel you get better value that way? I find that very weird.
Also, as has been said, these places work on averages. By unnecessarily raising their average cost you are contributing to them having to raise their prices or discontinue the buffet. if other people did it they would hurt you, why would you do it to others? If the price is good, then just eat what you feel like eating, without wasting. And if the price is not good, then just avoid it.
I find this attitude petty and very low class. People who do this kind of thing hurt the rest of us. i know a guy who lives in an expensive condo in downtown DC. In the lobby they offer free coffee. Since it is “free” this guy takes several cups up to his apartment every time he goes by the lobby and he takes coffee bags the machine uses and sugar bags. He says it’s free and it’s OK to do it but chances are they will soon discontinue the practice. The guy is hurting everyone with his behavior which is antisocial. Not to mention that it makes him look petty and cheap. No wonder he hasn’t had a date in ages. He’s a loser. Would you go out with people like that?
All I can say is, all this talk of “don’t do it! You’re evil! Isn’t a nice meal that you enjoy good enough for you?” is very un-Straight-Dope-like behavior. I applaud those who have had the guts to answer the question in a straightforward fashion. Why shouldn’t the man (?) get the most for his money?
“AARRRHHHHHHHHH. Come for the freak, stay for the food”.
For $5.50, as long as you eat a plate of food, you’r getting your money’s worth. Around the DC area, I’ve yet to find a decent Chinese buffet for under $10.00. Just eat what you enjoy eating and don’t waste food by loading up a plate and a soda and just leaving, that is both wasteful and rude.