I know this is $5 higher, but GameStop/Babbages/Software Etc.../Funcoland have had this game priced at $19.99 for some time now. Maybe I should start listing any prices I find at GameStop for certain hot titles...
However, my understanding is that the PC version sucks! Check online reviews -- sounds like it's worth the extra $$ to get one of the console versions. (Assuming you have one, of course!)
for $15-20 I'd say it could be worth it. Anything higher is overpriced. While there were some good points to the game, and it hold my interest (which is more than I can same for some other high profile FPSers), it did give me a bit of an empty feeling.
There were points where the plot seemed almost to jump ane made no sense. It was after I finished that I saw reviews for the console versions, and noticed that they had extra levels (including a driving mission).
I don't have a console, so I didn't feel that ripped off. However if you do have a console, get that version instead.