Hi Biking Mom.
I rode a TREK 1000 from 1989 through 2000. Back then it carried Suntour components (no longer). The 2005 looks pretty good for a starter bike under $600. I did lots of distance on my old one.
The WSD 1500 also looks real nice; has some carbon and a higher grade of components plus it's a women specific design (WSD). The price is a bit higher at just over $1K.
If you go with a 2004 model, you might be able to get a great deal at this point, what with the 2005's coming out.
I always liked the TREK products... I just happened to walk into a great deal on a Specialized when it was time for me to buy, plus I'm very comfortable on a men's frame (52cm). I'm 5'7" with a 32" inseam.