I never ride my SS mountain bike around town-- it's geared 32x16. I also never seem to find the time to take it off road-- so I'm thinking about converting it to an urban-commuter road / cross setup just for fun. I'm putting On-One Midge bars up front with road + cross levers (pulling either a v-brake conversion or some Avid Shortys) and slick tires.

I need to figure out a gear ratio that will be relatively fast for my 15 to 20 mile daily commute, but not steep enough to kick my ass on moderate hills. I run 48x17 fixed every day right now but I'd like something more relaxed for cruising and bar hopping. I therefore need a middle ground. What do you recommend?

I'd jump on my geared bike and find a ratio I dig but I don't seem to own multi-gear bikes anymore. Gah!