I like efficiency for my commute but the difference in comfort between 23's and 28's is huge whereas the difference in efficiency is below my ability to tell them apart. I run Continental UltraGators with kevlar in 700X28, I used to run them in 700X23.

Very puncture resistant, very fast, not as long wearing on the back wheel as some but I can usually get them on special at very good prices. I like putting on a tire whose grip characteristics I know well so I'm reluctant to change for now.