Hey My Friend And I Each Own One Of Both Tony Hawk 4 And Underground I Wont Tell You Who Owns What But I Would Like To Know Which You Think Is Better And Why... Cheers!

I do prefer Underground as opposed to TH 4, mainly because of the more free-roaming gameplay and "from nothing to something" kinda storyline.
However, I still think TH3 was the best of the bunch. It was the last one to be based on have those time-based missions and I sure do miss those.

wait until october to pick up the THUG 2. Should be better, plus who doesnt want to play as steve o.

I don't think THUG 2 will be as good as THUG. I saw a trailer for it and it's just team Hawk vs. Team Margera. But besides of that I think it'll be a good game.

Back to your question I prefer THUG because I like that you can walk and then jump on the skateboard which you can't in Tony Hawk's Pro Skater 4.And what I also liked was that you could design you own deck.

I just found the trailer for THUG 2 again. Watch it if you haven't seen it yet.

http://www.gametrailers.com/gt_vault/t_tonyhawk_ug2_e3_2k4.html