Yup. What Mr. Guy said.
The problem with a first lens is there's a sort of chicken-and-the-egg thing going on. Until you've shot with a lens, it's hard to know what you want from a lens. The folks who say "just buy the body and choose the best lens..." are typically people who already have experience with SLRs and know about lenses, and probably own more than a few.
But if you don't want to go the cheap-training-wheels route, there are three sites I'd recommend taking a look at. The first one is a lens primer: gives you the low down on the basic considerations that go into purchasing a lens: focal length, max. aperture, prime or zoom, third-party or on-brand, etc.
How to Choose the Best Digital SLR Lens
The second site would be Fred Miranda's review sections. You'll get a ton of reviews from differing viewpoints about any lens. From all the differing opinions, you'll get a good idea of the individual "character" of a lens.
FM Reviews - Main Index
Thirdly, there's a site that harvests through Flickr's lens-tagged photos, and offers up samples by lens. Remember that the lenses are often used with a variety of different camera bodies and with differing levels of skill and post-processing, but you can specify a specific camera body to narrow down the choices. pbase.com/cameras will also show lens samples by lens, but pixel-peeper.com tends to be easier to use for the more common lenses. Just keep in mind that folks will tag both pics of and pics taken with a lens with the lens name
Pixel-Peeper -- Over a million full-size sample photos from lenses, SLR cameras and digicams.