I'm biased towards older steel MTBs, especially from the mid 90's. Throw some slicks on, and you have a very fun commuter/urban bike. Get a disc tab welded to the rear, and you can still build it up with all the latest parts. With a Surly Troll fork, my Giant ATX 780 now feels like an great touring bike, and should be able to accept everything that a normal touring bike would. If I somehow don't end up liking my Masi, I'll probably try and turn another old MTB into a road bike.