I find the Ecco brand to be very comfortable - but naturally, it's all going to depend on what your feet are like and if you have wide or narrow feet, high arches or not etc.
In the meantime, here's a few examples of some that might work:
The Ecco Hanna - not a classic pump, but they're conservative enough looking and I am pretty sure they'd be very comfortable:
http://www.zappos.com/ecco-han.....cau-patent
(note: that one is available in black leather, the link keeps pointing to a purple-y patent, but there is plain black too).
Ecco Gisborne - again, available in black, but the link insists on linking to plum..
http://www.zappos.com/ecco-gis.....?zlfid=111
Meanwhile, I have heard good things about the Cole Haan shoes, here's a pair that might fit the bill, rave reviews on Zappos:
http://www.zappos.com/cole-haa.....?zlfid=111
There's quite a few options for Ecco - Another one that might work is the Gamboola style, but on Zappos, it shows only cognac - there is black available too.
Hmm...those Cole Haan ones look *really* good though.
Don't forget - Zappos has free shipping both ways - so the return is free too if something doesn't fit. I haven't done it yet myself, because I have a hard time finding shoes that fit me well, but I'm likely to order from Zappos myself soon. You get to try stuff on at home, don't have to go anywhere - ask anyone to get your size or what have you. Could be kind of nice