The PSP 1000 is only good if you want CFW. I have a 2000 and love it. The 3000 has the most features, and the brightest screen, and some of the newest versions of the 3000 have an improved analog nub.
The 2000 and 3000 are both worth the extra cost over the 1000.
I love the build on the 1k. Shame about the lack of features compared to the newer models. If I were you I'd either shell out for the Monster Hunter limited edition or hope for a PSP revision with it's features (better nub, grips on the back) to drop in the US.
There's no point going back to the phat at this stage. It's just too old to be worth buying used. You won't get trivial things like Skype support, faster caching, and memory bump even if you update to the latest FW.
I love the sturdiness and build quality, but buy a new bundle so you'll get a warranty to enjoy the latest PSP incarnation without worry. The 3000 screens make my phat jealous.
well, how low do you want to go for the -1000 models? I have heard people brag about getting one for as low as USD $50; but comparing it to later models, I think it is worth to spend an extra $50 to get a good used -3000 model.
3000 is the currently the best and has a great selection of bundles that are often at very low prices. you should pick one up on Black Friday somewhere.
2000 is a major upgrade over 1000 due to the improved d-pad. Perfect for fighting games! 3000 has this too but I don't think any of these can be permanently hacked. PSP 2 will be a lot more powerful than any of these soo I say wait for PSP 2.
The PSP 3000's screen is downright sexy. I hated the 1000 screen back when it first came out and refused to buy a PSP because of it. After I started playing with my MGS Peace Walker Big Boss PSP 3000, I was thoroughly impressed. It's a shame it took this long to get it right.