a mac is a mac , you can always ditch osx and install windows. and you can run both systems side by side. Thats the beauty of it. Trust me , OSX is pretty good for folks like you. You may find it hard at first , but then you will get the hang of it. Tell you what , for that kind of things a mac would do

I would suggest getting an iMac with Radeon x1600 . Just incase if you wish to do some gaming. have you tried OSX before

I suggest you to grab OSX 10.4 with PearPC to give it a try. It might be slow , but its just a nice way to explore OSX.