The 24v psu should be fine because he could wire the two pelts in series for 24v. The meanwell is pretty popular, but for $101 shipped you can get the
FSP-550, which is rated for 36 amps on the 12v rail, which is 432 watts, and of course there's the rest of the supply that can power your computer. I have the FSP-550, and it has no trouble powering my oc'd computer with 3 hdd's and a cd drive PLUS my 226 watt peltier. For the peltier I was using the 8 pin EPS connector (4 12v and 4 ground) which I thought was perfect for the pelt, but after weeks of running without the connector even getting warm, the connector started to turn yellow
so I gotta add another connector or two because I don't want to void the warranty by cutting wires.
It would definately be pushing it to power an oc'd computer with a 226 watt pelt PLUS an 80 watt pelt, but I wouldn't say it isn't possible. What I would do is buy the FSP-550, expecting to power only your computer and 226 watt pelt. If it is miraculously able to also power the 80 watt pelt, that's gravy. If not, you won't need anything special to power the 80. You could probably use a supply that you already have. Anyone know how much current an 80 watt pelt draws at 12v? The Imax is only 8.0 amps, Vmax 16.1v, so it won't be much.
Going the meanwell / FSP-530 route will cost twice as much. Play it right and you could be spending as little as $101, not counting the possibility of the 24v supply, which is also an option.
EDIT: also as an FYI, I have heard one report of the FSP-550 pulling 40 amps on the 12v rail before shutting off, but I can't verify this. If you want to send me the 80 watt pelt, waterblock, and necesary tubing/fittings/electrical connections I'd be happy to test it alongside my system + 226 watt, but I don't think it would be worth the extra time and money because even if it can't handle both, I still think you'd be better off with the 550.