From just looking at prices when I was shopping around, Campy tends to be a little more expensive then Shimano, so you may want to stay away from them if you're on a budget. Trek owns Bontrager I believe, so they should come with their wheels standard. Most bikes that I saw in the ~$2k range had 105 w/ Ultegra RD. Not sure how the 105 compares to the Ultegra, but I was told the main differences between components is just weight. I'm sure someone else will chime in tho.