As far as I know you can just replace with any PSU. The only company I know that use specialist PSU's are Dell and the only difference is the pin layout.
It's always a good idea to make sure all connections are included on a replacement in case your motherboard has a special 4 pin connecor, usually for newer computers that require a CPU power supply.
If getting a new unit I would steer away from the cheaper names that offer high power and go for a better company with lower output. The high output models from cheaper manufactures refer to peak power - the continuous power delivery usually falls very short of this figure. If you use a better unit the quoted power would be continuous, these units also provide better stability etc.
I currently use a Tagan unit, only the low power model and I currently run an Athlon 64, 1gig, 2 x 200gb HS's, DVD writer and DVD rom + several fans and a Radeon 9800 AIW without any problems.