Personally, I think this is the way to go. I use a Saitek P3200 pad, which has the same button layout as the PlayStation controllers, apart from a button to turn the analog controls on and off. It also comes with the rumble feature. I'm sure you could get something of a better overall quality, but I picked this one up when I first got my laptop for about £10, and I've never had any problems with it.Instead, you might want to look at getting a PSX look-alike controller like the Logitech Rumblepad 2. A wireless version is available and it has much better driver support (including 64bit) unlike most of the crappy drivers that often come with a converter.
Hmm. That's lame..I thought they had official drivers.