To my knowledge, SSF4 isn't getting a PC release at all.
That's fine, since I'll be getting it for the PS3.
The reason why I'm reluctant to get the original Street Fighter 4 for PC is because I will be picking up Super Street Fighter 4 when it's out in a few months, and really, spending $60 on the original, $40 on the PC port, and then whatever on an upgraded version would be overkill for me. Street Fighter 4 is good, but not good enough to have justified spending $150 in total or so.