I voted slow 35, fast 50 before really reading the op. Since I'm sticking with Summicron 35 IV and Summilix 50 ASPH, I guess it's fast/fast, but as far as the speed preference goes, I still prefer faster 50.
I've considered myself a 50 guy, but I'm getting more comfortable with 35. I like small 35 for travel, and often faster than F2 35mm lenses are quite large/long. As far as the speed goes, I feel F2 is fast enough for what I do for the most part, and I'm kind of treating the fast 50 to be a short portrait lens where more control of DOF could be handy.
Ideally, having both fast and slow (small) 50s would be perfect, but I can get by with just a pair of said 35 and 50.