I don't know too much about Vanderbilt, although I'm sure it is an awesome school. I do know some things about Baylor that might help factor in your decision:
1)The clinical affiliations (Ben Taub, Houston VA, St. Luke's, Texas Children's Hospital, Menninger Clinic, TIRR, etc.) in the world's largest medical center, Texas Medical Center, are all awesome
2)1 and a half years of basic sciences and 2 and a half years of rotations rock (apparently this helps your residency applications and helps you to do better on Step 1 USMLE)
3)Baylor students I've met all seem really smart but at the same time pretty laid back
4)BCM has that "great school" reputation amongst residency directors, which will be useful when we apply for residencies
5)Baylor students have top 5 in the country board scores, another residency boost
6)Tuition,especially for a private school, is an amazing deal
7)I think nearly 50-60 out of the 149 people that matched for residencies from Baylor in 2005 ended up staying there for residency, showing that they like to take back their own for residencies; Match lists are also impressive, with traditionally hard to get into specialties like dermatology, ENT (11 last year!), ophtho, etc. doing well
8)Cost of living in Texas is really cheap
9)Classes are mostly 8-12 PM; all lectures are recorded on video, and can be readily downloaded in real media format to view at your leisure
10)community service options as med students are also really good
11)Multiple track s you can take within the curriculum: Research, Ethics, International Health, Geriatrics, Care for the Underserved
12)Dr. Michael DeBakey, world famous heart surgeon, has earned his name while being at Baylor and in the process put Baylor on the map