It's OK to have slightly smaller tubes than your tire size. I've used 23-25's on 28C, and 32C tubes in 38C tires. They expand just fine, and to be honest they're easier to install since it's harder to get them stuck between the tire and rim.
I love Vittoria Randos. They're heavy and pretty slow, but are all around great tires for commuting. There's slower tires (Marathon Pro) that are better at stopping flats, but they cost twice as much, and seem like over kill.
If you want to take the hassle (and cost) out of good flat protection, any grab any slick tire and Mr. Tuffy tire liners. After the 2nd pair of tires you end up saving a lot of cash, and they work better than almost any tire with flat protection built in.