GW Bush. I’m still praying he was just a fictional character and the last 10 years was just a horrible, Dallas-style dream.
Other than that, I would hang out with Alf.
Hurley and Ben from Lost.
Lorelai from Gilmore Girls, but only for short periods at a time.
Can “friend” mean “friend with benefits”? If it can, then I’m gonna grab Richard Alpert from Lost.
Blasphemy! Lorelai’s only faults are that she loves Luke instead of me, and her maddening habit of not constantly wearing mini-skirts!
Dr. Who.
Dr. Jonas Venture Jr.
I…don’t watch much regular tv.
Moving back in time a bit, I’d probably get along well with Maude from Maude. And I’d like to think I’d enjoy knowing Dr. Johnny Fever.
Yeah, I haven’t watched much TV since the '70’s.
Dexter. I think he’d made some of my bad situations better.
And Veronica Mars. Same reason, less bloodbath.
Data from Star Trek is definitely the best answer so far.
Have you considered the downsides, though? The police would be constantly coming by and asking where he was, he’d probably want to stash Rocky at your place until the heat was off, he’d always cancel fishing trips at the last minute, and there’s a very good chance that somehow your car would get wrecked.
Hands down Vincent Chase. Just basking in that overflow ala Johnny Drama while doing nothing is an amazing dream.
Sam from Burn Notice; he’s not as dangerous to know as Michael and Fi but can still be very handy to have around, and I’ve got a couple of spare bedrooms that I can trade for his services should he need an overnight safehouse from time to time.
Other than the fact I don’t have advanced degrees in science I’d probably get along better than I’d care to admit with Leonard, Raj, and Howard from Big Bang Theory. (Only his Meemaw ever got along with Sheldon.)
Robin Masters.
Dibs on the Ferrari!
hmm. probably Tommy Bolero from the “West Test Rolling Best”
(He is the guy owith his arm in a cast)
If I were a teenager I’d have definitely been friends with Rachel, Kurt and Artie from Glee. When I actually was a teenager I used to dream somebody like them would transfer to my school, but as was I was the only one who could appreciate showtunes as even the girls were into country and pop.
Cliff Clavin (from Cheers) - the man was a fount of knowledge!
You know, Arn, there’s an interesting story about that… the phrase fount of knowledge comes from when they used to open up the heads of brilliant people and let it spray over all the villagers in the hopes that it would make them smart… this was back just before Delaware became a state you see… 
Really? No votes for Tim the Toolman Taylor? He’s my own personal jesus!
Rhoda
Alex Reiger
Elaine Nardo
What’s up with all the Rockford love?
Wasn’t he like a 45 year-old single guy who lived in a trailer (down by the river)? *
*I barely remember the show