First of all best place to get a bike IMO is Bikesdirect.com
Lets be honest with ourselves... we are not going to be riding on dirt trails or in the rain. Ive done both and they suck. Plus they would leave u all nasty for work
Even though your commute is only 2 miles, u might eventually want to ride more, which requires comfort. So a bike with comfy ergonomics is key.
I bought wifey a bike last year, and I'm kicking myself for not getting this one. It's a crazy bargain and prob the best $300 you can spend on an all purpose road bike.
http://www.bikesdirect.com/products/gravity/avenue_b.htm
Just make sure u get ur size right and get it assembled if u dont know how (its pretty damn simple though)
Im probably gonna sell my road bike and get this. They are great bikes for casual riders.