I'm living in Seattle, plenty of hills, and was using a 44 x 17 -- fun.

I went up to a 46 x 17 on my new build and found that, while it's a bit tougher on the climbs, I'm not at a loss for anything and to the contrary as my legs get stronger I'm faster on the hills and on the downhills as well.

It's generally too steep to rock a 44 x 17 going downhill in Seattle most of the time, but the 46 x 17 is very nice.