When we had to shop for a diaper bag (wow, this seems like such a long time ago!)I specifically looked for a style that doesn't look anything like a diaper bag and for something I could use after my son graduates from his nappies.
We didn't have to look far as I immediately found what I wanted. Alonzo's Skip Hop diaper bag has served us well for the past 3 years.
Surprisingly, it still is in pretty good shape considering all the abuse it had been subjected to.
It is what I use now for my laptop and other stuff!