Haha, sorry, I didn't mean for you to take the mac comment seriously. That was just me having a go :3
I have played Uncharted and I enjoyed it. It is a good adventurey shooter, but you can't seriously compare GTAIV to it. You just seem to be entirely missing the point of GTAIV. It's not meant to be played like Uncharted - a series of mostly linear encounters. It's meant to be messed around in. They deliberately make it ridiculously easy to lose your wanted level (go to safehouse and sleep) so that you can fuck about as much as you want and do generally awesome shit as a nice break between story missions. They then tried to expand on this with friendship maintaining which was a dreadful call, but you can just ignore them. Only problem is you miss out on some sometimes genuinely hilarious dialogue if you do.
Going back to the earlier mentioned Mafia 2, I think you'd actually prefer it to GTA, because it has a big sandbox city which then offers NOTHING AT ALL TO DO IN IT other than the story. The shooting in it is spectacular, especially if you have a physx enabled card and it's a game you could reasonably compare to Uncharted. Both good, fun, solid shooters but absolutely nothing more.
I prefer my games to take themselves less seriously for the most part. Exceptions being the HL series, Mass Effect series and Dragon age, all of which are held expertly together by gripping narrative and extremely identifiable and likeable characters.
Uncharted and Mafia 2 are more like Mirror's Edge in my view - they're great to play through once, but they had no lasting effect on me and I'm probably never going to play them again.
tl;dr:
GTAIV doesn't take itself seriously. Neither does the Fallout series. If you accept that and just enjoy messing around with them, you'll find a great deal of enjoyment.
Huntey's top 5:
1. Fallout 3/NV
2. Mass Effect 2
3. Half-Life 2 & Eps
4. Dragon Age
5. Bad Company 2 (Online only. Singleplayer was a bad joke.)