Depending on how my finances shake out in the next few weeks, I'm thinking about buying a PS3. I have a few questions, though:

-Is there any reason not to get an older, PS2-compatible model?

I don't think you'll be able to find an older model that can run PS2 games that isn't brand new. And with all electronics, I'd advise not buying a used one. I had a Backwards Compatible 60GB that lasted me two years, but I hear the Slim's are better on electricity usage and are able to last longer.

Again, I suggest buying a Slim. You get, what, I think 120GB for the same price as any other model? I could be wrong though.

Sorry if I totally misunderstood the question.

@DevWil: Just get the 120 Gb slim.  Trust me.

...but...

so many ps3 games have mandatory installs now I wouldnt recommend a 20gb.

The PS2 compatible model has a much smaller HDD (60 GB), but It's been enough for me. I don't store any movies or anything big like that on it and had to maybe delete a few bigger demos but it hasn't really been an issue.

I'm not sure if it's that easy to get, though, and even if you manage to find one it'll propably be used.

I didn't have any major problems with my launch 60 GB PS3 (used extensively, mind you), although it freezed on me a couple of times and had to be restarted. But it only happened a few times during the 4 years I've had it so I can't really complain.

EDIT: Persona 4 also worked like a charm on it ;)

I put in a 250gb and it's nearly full, but I use my ps3 a lot.

" ...but...

...persona 3 FES and shit.

"

I have 7 games for my PS3 and 40 GB isn't enough for mandatory install games. You do know you can put your own hard drive in there? Make it like 1 TB.

" I have 7 games for my PS3 and 40 GB isn't enough for mandatory install games. You do know you can put your own hard drive in there? Make it like 1 TB. "

If you can find a 60 gig BC PS3, do it. Mine ran like a champ for almost 4 years. Just upgrade the HDD, it's cheap to get at least a 250 laptop hard drive these days.

Your decision comes down to risk vs. reward. How important is backwards compatibility to you? Are you willing to risk buying a used 60GB or 20GB console that could yellow light on you at anytime just so you can play PS2 games, or do you want a new PS3 sans backwards compatibility that will be more reliable in the long run? The decision seems incredibly simple to me, but again, it depends how badly you want backwards compatibility.

" ...but...

...persona 3 FES and shit.

"

The Backwards Compatable models have a higher failure rate (but it isn't huge) because of that I'd get a slim and hold on to a PS2. As far as hard drive size you can always upgrade it super easy but 40gb should be a good start

I wouldn't go after the 60gig BC model just out of YLOD fears, also you don't know how the thing was treated before you got it, for hardware it seems like a fresh clean system is the best way to go and generally not much more expensive.  And honestly, I haven't played a PS2 game since Persona 4 after getting my PS3, there's just a ton of great stuff you can pick up on the cheap that should keep you flush with games as long as you don't mind playing some older ones that should prevent you from spending $60 on a new game unless it's really special.  I'm running a 250gb slim and it's worked like a charm.  I've used about 70gb for installs, downloadable content, and downloadable games so a 160gb should do fine as long as you're not having it double for media storage (at which case, you're probably getting your own HD to upgrade it with once they get that functionality fixed... is the data transfer still kinda busted?)

thanks everyone.

To be honest I had a 60gb model but I thought the hardware chip on mine was not impressive on my hdtv, I have a standard def tv where lies my PS2, I suggest you buy a slim, but seriously there are too many games on PS3  now to even think you'll be playing old games outright on a regular basis to seek a fat PS3.  Back then maybe but not now.

I would strongly recommended you get a slim. The older models are known to get the yellow light, and i have first hand experience, its a painful experience IF it were to happen to you 
 
Although i know people with the original 60gb launch model that still have no YLOD, so i dunno, its up to you 
 
You could always buy a cheapo PS2 to play ps2 games