The Original made in 2000, Source or Global Offensive? I'm thinking of getting one from steam, but their ratings are pretty close. Except for Global Offensive, which is quite a bit lower. But it's much newer. Graphics don't mean too much, it's gameplay that matters =/
I am thinking Source is the right one to get. It has the biggest community, most mods, most hardcore fanbase, and overall I think all these things make it the most fun. Personally, of course.
I was talking to my friend about this yesterday. He's been playing since the original and said that although there are people who will always swear by Source, he thinks most of the community has acknowledged that GO has taken over as "the place to be" and is the best place to enter the series. I was going to pick it up myself, but I just missed the sale.
As someone that has spent hundreds of hours on Source (not much compared to my friends, lol) I think GO is a bit derpy. When you look around there is a sort of acceleration that I don't like even when mouse acceleration is turned off. 1.6 and Source are snappy and have no delay/acceleration. The guns in Source feel much better, but that's just my opinion. I feel as if all the guns have the same spread in GO, and the recoil on some of the guns is too much.