If you're commuting, then one extra red light can kill your commute time...even if you're riding a 15 pounder. The lighter wheel may net you 0.1mph going up a grade. That's noise in my book. Day to day variation in wind speed has a much greater influence on your commute time than a lighter bike.

In general, you want to avoid a tire with high TPI rating. A low TPI number translates to a larger thread, and a more puncture resistant tire. I ride Michelin City with 33 TPI. Only one flat in almost 3K miles. The culprit was a tiny wire from a delaminated auto tire. The Michelin Pilot comes with a thick 3mm breaker, instead of the 1mm breaker found on basic City.

I had a 21lbs Cannondale. Currently ride a 24lbs Bridgestone. My 19.6 mile commute is still 65 to 80 minutes...head wind in one direction, tail wind in the other.