Tejada is a top three SS, at the least a top four.
Bagwell isn't really even a top five 1B, Pujols, Helton, Delgado, Thome, Sexson, Giambi, are all better IMO.
In addition there are a lot of tremendous value picks at first base that are available later in drafts: Big Hurt, Aubrey Huff (not much later, but later), Sweeney, etc.
Tejada is a much rarer commodity. I'd definitely rather have him than Bags.