im new around here and after looking at this it looks really fun, so im thinking about buying the PC version of GTA 4 so I can play this. I have a few questions,

Do I have to buy GTA 4 from Steam or can I buy the regular PC version?

Is it worth playing?

I think it is very worth it especially if your in a good community or by your self. I my self got the disk version which I could only find at target. But the thing about GTA IV it takes a little bit of work to get the mods to work right with each other because some mods may overlap on what they do by pressing a certain key and you may have to change it, but when u get it set up good it will keep you up playing all night. Also quick tip go to this website to make sure your computer can run GTA IV  http://systemrequirementslab.com/

Thanks for the feed back and i do believe i will be picking the game up later on today and i have to say i am REALLY excited about trying this out.