Like Trekker said above, I'm not a fan of suspension for anything that isn't technical Mt. biking. It's extra weight, it sucks energy and it's another (expensive) part that can break. A lot of this is taste and personal preference...and it depends on your preferred riding style and things you need in your bike (will you be carring anything? will there be dirt or gravel portions of your commute? how are the streets there, how are the hills?).

I like drop bars (many don't), 28c tires and fender clearance on my commuters. I want something reasonably light weight (under 28 LBS) so that I can carry it in and out of my house easily. My favorite commuter is thus my Raleigh International...it's perfect for my needs. I also have an internally geared Surly Cross Monkey I use depending on weather conditions. I'm less crazy about the KM because I really like drops, and that has mustache bars...also it doesn;t take fenders.

I think a lot of the time the most cost effective and practical way to go for many riders is a rigid steel mtb with braze ons for fenders and racks. I had a bike like that and LOVED it as a winter rider...I would have gone over to drops and used it as my main commuter, except the internal geared thing won me over and I replaced it with the Surly. In retrospect, I'm not sure that I made the right move.