From what I have heard (although I don't quite have experience with an SSD yet) is that it's better to use both an SSD and an HDD. I know a person who uses both on their tower and they use the SSD for programs and the OS install and the HDD to keep files.
If possible, this is the setup you want to go with, as the storage of an HDD per GB is still miles cheaper than an SSD.
As for the PC in the OP, I'd be concerned about that Cooler Master PSU it's using. Cooler Master doesn't have the best reputation as a PSU manufacturer (their system cases and aftermarket cooling systems are amazing, however). Breakdown by itme:
Mobo: Great budget buy.
Processor: A nice budget processor. Not top of the line, though.
Heatsink: Great heatsink.
RAM: Generally considered quality RAM. Is it DDR2 or DDR3?
Video Card: Nice budget video buy.
Hard drive: Need more info other than the brand and size.
Case: Great case.
PSU: Iffy since it's a Cooler Master. If it's the bronze certified one (second version of it), it's okay, but not great. The non-bronze certified one is terrible, however.
All-in-all, it's severely limited by its PSU. It needs a better quality PSU. The wattage is fine, but you need a better quality PSU than the Cooler Master GX 650W. I'd suggest looking at Thermaltake, OCZ, or Corsair. Especially OCZ or Corsair.