My first non-department store bike was, perhaps ironically, a Mongoose. It was a 2nd gen Rockadile (1993). Basic and a bit heavy, but at the time it was a pretty darn good deal considering the components and all-chromoly frame. And it performed quite well offroad. Up until recently I was still using it as a commuter bike, but feeling it was time to give the poor bike a rest, I converted it to my cargo/utility bike, so it sees much less use and doesn't have to be out in the rain as much. A few years ago I built up a Surly Long Haul Trucker as my ultimate commuter bike, but my Rockadile was literally better at everything than the LHT, so I put it back into commuting duty.