Thanks for the replies!

I hadn't really considered altering my mountain bike, but I suppose I could consider it. The main reason I was thinking to replace it was that I got it when I was 14, so its a little on the small side nowadays (though not too bad), I suppose I could get a longer seat tube and such...

It's a GT All Terra Outpost Trail, from the mid-90s. 4130 triple-triangle frame, shimano SIS SL-TY31 thumb shifters, shimano altus C50 deraileur, rims Weinmann 4019 26x1.50/550, 18 speed (3 front, 6 back, 5 of the back five are rusty). It works alright but was stored outside while one of my siblings borrowed it last year, so is in need of some TLC.

I was mostly thinking something newer and lighter would be nice. My wife has a hybrid as well, and we were thinking it would be nice to go for rides together. Maybe fixing up the mountain bike would be enough, though I do like the idea of a new bike... How much of a difference will the 26 inch mountain bike slicks vs. the 700c hybrid tires make?

Sheesh, now I have even more to think about! I hadn't even thought about the possibility of heel strike, I'll need to think about that. Can that be fixed by different rack/pannier combinations, or is it just bike/foot size? I'm a size 10.5, so not bigfoot, but I can see how that would be a hassle.

Back to pondering!