There's also the fact that a bright flashing avatar such as that one could be potentially hazardous to someone suffering from epilepsy or a similar disorder...while I don't think we currently have any members in that position, its certainly something to think about...
Anyway, I'd like to second Tom's recommendation to shorten your signature and think about putting your list of machines on the wiki. Really...I think by now we all know how many of what Macs you have and all, and those who don't...well, they should know where to go (the wiki) to find out.
Mars478: His avatar is an animated PNG - a format which is only supported by Firefox and maybe a couple of other browsers. Just, guys...please, just don't use animated avatars of any kind.