If you're not planning on doing any off-road riding, a rigid fork is a great way to go. Only caveat - try and figure out what the travel is/was on the old suspension fork. The Nashbar one you linked to looks to be about 100mm. Even if its too high, you should still be able to ride the bike with the new fork, the steering just might be a little weird for a short time while you adjust to it. And yeah, rigid MTBs are great all around bicycles.

FWIW: I just ordered on of those Nashbar forks, too. I'll be using it to replace a cracked rigid fork on an early 1990s MTB, and I wanted the extra 'lift' so I could get rid of the stem extender I'm currently using. If my calculations are correct it should work out nicely.