To me, a good ad is one that makes tou pause the TV and go back to watch it, or take the tube off mute. The ones that do that consistently for me are the ads for Jack In the Box.
And an oldie: Little Sister.
Too Much Transparency has me laughing my butt off these days.
This PSA for condoms is outstanding.
A glasses place had some ads where people needed new glasses, like a woman bringing what she thought was her cat inside to snuggle with, but was really a skunk(or raccoon?).
I remember finding them actually funny and great.
Old Spice is starting a new series of bizarre commercials, and this one is pretty great.
It’s a fine ad, until six days later when you still have The Mamas and The Papas running on an endless loop through your head…after that, it tends to wear a bit…
It got my attention right away. But after seeing it about 6 million times in the last few weeks. I hate, hate, hate it.
Here is a recent one one that was eye catching
Prolly better viewed in Hi def full screen
How do you promote CPR? - like this
Stereotyping is the advertisers stock in trade
Honda
Virgin airlines
Grand national
The only commercial for which my daughter and I actually turn up the volume on our TV. We even sing along and sometimes do a gypsy dance to it:
Love that Count! 
This one made me laugh my ass off the first time I saw it.
Not that I’m a fan of the organization, but I think this ad gets the idea across very well:
Here’s one I posted in another thread a while back. The twist at the end still gets to me:
Here’s one I like because it’s so direct. No marketing BS - it just tells you what the product does:
The original KIA hamster ad was cool.
Oh my goodness! That one made my eyes tear up!
This is the one I came to post. I couldn’t stop laughing for 10 minutes after it was over. Then I had to watch it again, and the cycle began anew.