I am very happy with the results from my Zoom 5341J so far, but it has only been a week or so, but so far performance has been spot on. Heard good things about the Motorola SB6121 as well...
I would steer clear of the Cisco / Linksys DPC3008-CC. I had that one in mind at first, but after reading the reviews, it looks like it isn't a good modem...