For the CPU, as always, my recommendation is this.
Throw the best combination of IPC and frequency at it as you can. That's the key. Just make sure it has at least two cores (more than two adds nothing, but hurts nothing either). Overclocking is almost a requirement.
Currently, a Core 2 based CPU at about 4GHz has proven to be cheap, easy, and fast. For that, I'll recommend the Core 2 Duo E8400. If you can ensure it'll be the E0 stepping one (are C0 stepping CPUs even still in stock?), then definitely go for it. You may reach 4.3GHz or higher on the right motherboard. I have experience with a Core 2 Duo E8400 at 3.6GHz and 4.05GHz, and my current CPU at 4.0GHz and 4.5GHz. Really, all configurations pretty much flew through PCSX2.
As for the GPU, it doesn't matter quite as much as the CPU for PCSX2.
The GeForce GTS250 seems a good sweet spot though, and will also play games decently. The GTX 260 is also nice, and will make it better for PC games, since it's the faster 216 stream processor version.
@rama2: yeah, good to know... but neckermann.de offers a "monthly installment deposit"!
btw... i searched the web but couldnt find anything... im also interested to buy a notebook... would you recommend a notebook with an "Nvidia Geforce GTX 260 M" graphic card and "Intel Core 2 Duo P8600 2.4 GHz" processor?
I wouldn't, no.
The problem with notebooks is that you pay a very high premium, and still just get "ok" hardware for it.
In this case the gpu is fine, but the cpu is not fast enough for trouble free gaming (with pcsx2 ).
Just to clarify, you need a 4Ghz core2 + a decent vga card.