iggyus said:
Should I get a new one or buy a used one? Also should I go for the classic or the Slim? I have played on a classic a few times and I love it but is the Slim any good?
Here's the thing about the PS3 that really dictates which model you should buy; preferance. Older PS3s had more functionality and options to them, but were more expensive. Remember that whole 500 to 600 dollar phase? That's cause inital models were dream boats of functionality. Later models were stripped of this to make them cheaper.
I have an original 60 gig model. That means I have flawless PS2 backwards compatability. For me, this matters, since I still play ps2 games from time to time. (there's more to the model, like 4 usb ports, wireless modem, etc.)
The Slim model has stripped down functionality, but a bigger HDD out of the box (PS3 HDDs are upgradeable), and less expensive.
If backwards compatability doesn't mean anything to you, but saving money does, then get a slim.

You'll be happy to have the extra gigs. If functionality matters, try to find one of the older 60 gigs.
(There are 80gig models that try to emulate ps2 functionality, but they're only 88% reliable with their backwards compatability, and efforts to enhance that percentage have been dropped.)