The following feeds have been edited to point at a working URL:
sinfestfeed, boondocks, doonesbury, foxtrot_feed, reallifecomic, megatokyocomic, calnhobbes, nonsquitor_feed, dorktowerfeed, kevinkell, errantstory, pennyarcaderss, dilbert_feed.
dilbertdaily still doesn't work, so if you're watching that, switch to dilbert_feed.
edit: And, in my typical style, I've messed up the URL for errantstory. I'll get that one fixed soon.
I have also added the following feeds:
fbofw_feed - For Better Or For Worse Comic (For Better or For Worse)
someposifeed - Something Positive Comic (here)
littlegamersrss - Little Gamers Comic (here)
cathy_comic - Cathy Comic (here)
For those of you who watch these feeds - thank rahaeli for changing the URLs, and ME for making the feeds ;) These things are all hosted by me, so if they break, please let me know, by emailing me at firstname.lastname@example.org.