For the last 4 years i've been commuting with a backpack for short commutes (4 miles round trip).

I just moved and now my commute is 10 miles round trip. At the end of the day my back has started to kill me and it's just too hot in Texas in the summer.

Today was the first day I used my backpack bungie-corded to the top of my rack. The ride was hugely more enjoyable, I felt great at the end of the day and felt I could ride another 20 miles if I wanted to.

I'm definitely getting panniers, just have to figure out which one!