Just another plug for REI. I bought my first mountain bike there this winter, and they were really, really helpful and nice. Also when I took it in for my warranty tune-up. The folks at my local REI (ymmv, of course) know bikes and gave me the same type of attention I'd expect at an LBS, so just because it's a big chain, don't rule them out, especially for lower-end bikes. I got a great deal on last year's model in the MTB I wanted and good service to boot!

Emily