I normally commute on a Trek FX bike which weighs somewhat like 30 pounds with fenders and rack (no panniers). No suspension and the front fork is straight and aluminum. No drop bars, as I like flats for commuting (and also I've never ridden on drops ).
Well... Today was different. I borrowed my friend's Trek Hardtail MTB. He was riding it with wide slicks and had everything greased and the suspension tuned well. I've never enjoyed the comfort of riding over cracks, bumps, potholes, or anything else Michigan roads make us endure more than on that bike. I LOVE IT!!! Yeah, it was only like a 3700 series, but compared to my hybrid road it was like butter!
I don't know... It was a 16 inch frame and thus weighed less than my hybrid road and it was such a really comfy ride... I might just have to invest in a hardtail with some ample front suspension for commuting