you are stuck with Mac software. Yes many applications have a Mac versions- Photoshop etc. But you wont get the huge range of PC stuffthat is out there - Then perhaps you wont need it. Surf a few Mac sites and forums to see what it is all about.
see the postings on this page click here= I had a 20inch several months ago and returned it as the variable colour as you scrolled down or side to side rendered it useless for video editing. I did not know this problem existed when I bought otherwise I would have given it a miss. Previous imacs were OK. Some people say the 24inch was less affected but at the price you are paying you want to be 100% happy before you purchase. It would seem Apple are not doing anything about this problem but there are rumours about a new type of screen