Legend was good, but a little too short compared to the original games. I haven't had a chance to play underworld yet. Any good?

It was more of the same, actually less so, because all the collectibles were generic items.  
 
That's not actually a huge thing, it's just the only thing I can think of because they all blend together at this point.

yea i completely agree with what your saying. as much as i love tomb raider, theres only so much you do with it before it all feels like the same.

First off, Underworld is TR8, not TR9. Anniversary is a remake. It doesn't have a number. I know this because I know one of the developers personally. The next game is being referred to as both TR9 and/or Tomb Raider: Origins. Just thought I'd straighten that out.
 
As for my opinion on the matter, I like Anniversary the best. AOD has bad controls (but it's good), TRL is trash, and TRU has far too many bugs.

Angel of Darkness is my favourite overall, better then Legend by far IMO

Legend.. it was a long needed reboot, and giving the series to the Legacy of Kain guys really helped.  It returned the series much more to its exploration/puzzle roots.  Rather than the action slock it had developed into.  Anniversary was good too, but ruined many of the memorable scenes, particularly the T-rex being a QTE boss fight, instead of a huge obstacle you were supposed to avoid.. 
 
Underworld was a good cap on that trilogy, and it had some really great levels.  But it was rushed out by Eidos.. way too short and suffered from a lot of bugs.

For me it has to be Tomb Raider Anniversary. It has the new tomb raider style (which at its base level its like the original game but "smoother) but also harkens back to that original feeling of lonely and fear I felt as a 7 year old when I first played the original game.I also loved the way it felt like an original game but the way it had all the main spaces from the original game but in a completely new way was amazing.

Though I also love Legend and Underworld (though I liked Angel of Darkness too just not as much) it was fun as an original game but it dosent feel as steeped in lore as Anniversary and felt more like just an action/adventure game so although I loved those games it almost felt like it wasent a Tomb Raider game.