A 24mm pancake would be another great option. It's as wide as I and most others generally want to go on 135 format for typical stuff, and it's the same almost-exactly-textbook-normal focal length on APS-C as the Shorty McForty is on 135.
But there would be a lot to be said for a Holy Trinity of pancake primes (a Short Stack?) in something like 20-40-80.
Assuming, of course, that all three are optically comparable to the Shorty McForty....
Agreed, I've been uhhhming and ahhhing for some time about which one of the new primes to get for my 7D as a walkaround lens, the 35 IS appeals to me because it's 2 stops faster than my f4 lenses, but it's fractionally longer than a 50mm on full frame, the 28 is just slightly wider than a full frame standard lens and the 24 is closest to the 40 pancake, but both the 24 and 28 are only f2.8. I like the thought of a slightly wider than standard compact stabilised walkaround lens, and the 24 comes closest...... but the 35 is faster..... decisions, decisions .... Still, the longer I wait the more they come down in price!