HuffyMan,
I am also new at this stuff so have only limited qualification to comment, but here is my 2 cents worth. From what I have read and heard, I would not buy anything less than 105 in Shimano. You can look at some of the parts and see a definite difference in the finish and at least the apprearance of durability. I may be a little prejudice though, because I just spent a bunch of money upgrading to 105. After that, let me assure you that the extra $600 for a complete 105 group is a bargain. I have heard it this way, that there is a big step up in quality from Tiagra to 105, but from there to Ultegra then Dura Ace becomes more a matter of weight savings.

On the other hand it seems that even the lower end Campy groups are pretty good.

Other comments?
Regards,
Raymond