I have four routes I use, with variations for them all. I'm fortunate too that my commute is always off-peak. I start in the early afternoon and work until closing. This also explains why I take a long way to work more often than coming home.

Winter route - 4.3 miles
When the side streets I generally use aren't sufficiently clear, I stick to major arterials. I don't care for it otherwise--too much traffic, too many buses, too many stoplights.

Default route - 4.7 miles to work, 4.5 miles home (due to a one-way)
Except for crossing the river, this is primarily residential streets with a couple of secondary "collector" streets thrown in. I use this most often coming home and it's my typical route both ways in winter. It's great for sprint training with 12 stoplights, 8 stop signs and a roundabout. Stoplight intervals, baby!

Hills, parks, cemetery and trails route - 10.25 miles
A line of hills form the southern border of the city. I string 'em together. Climb and descend through Cobbs Hill Park, residential streets up and down and up and down along the north face of Pinnacle Hill, climb to Highland Park, descend to Mt. Hope Cemetery, choice of three climbs and a bunch of rollers through the cemetery, cut though University of Rochester's River Campus to Genesee Valley Park, take the Erie Canalway to the west side, double-back on residential streets. I like to take this route to work at least twice a week in the three-seasons.

I'll use it coming home every now and again, but never again during standard time. They close and lock the gates around sunset. I got locked-in once. Had to lift the bike over an eight-foot wrought-iron fence, hang it by the headtube on a spike (fortunately it was the Ti bike so it was light enough to do this, and it has no paint to scratch), climb over the fence myself (no small feat), and lift the bike down from the spike.

Long loop - 16.5 miles
This starts on an arterial heading six miles in the wrong direction (East), I connect with the Erie Canalway using it for about nine miles west, which overshoots work, and I double back for a mile and half on residential streets. In the three seasons I like to use it at least once a week in each direction.

In the cemetery, I get a choice of two cobbled climbs.