My 1995 Raleigh M Trax, Ti/steel frame. It's the one made by Dyna and assembled in Raleigh Special Products. It's an old school 90s MTB on slicks that has just been worn to fit me like a glove after 20k+ miles. I rode it 90 miles in a day last month, so it gets plenty right. That said, if I really DID have to go to one bike I'd chop it in for a hybrid that had identical frame geo and disc brakes. The only thing that makes my old bike feel 25 years old is rim brakes. Yes, they work, but discs are better. I also have 2 drop bar bikes, I'd trade them both for a hybrid running say 30-35 x 700, flat bars, bar ends and Shimano thumbies.