I'll cast another vote for the Astron switching power supplies. Small, light, and I have no RF problems on VHF/UHF. Since Astron is in the business of building power supplies for radio communications, I'd like to believe they pay attention to eliminating the RF hash that some switchers generate.
As for sizing the supply, I like the idea of getting one that is about 50% oversized for the largest load. And, unless you plan on keying two radios simultaneously, you can use the radio with the highest transmit current to do your sizing. Most radios when in receive mode draw a fraction of what they draw in transmit.
Also, pay attention to how the power supply is rated. Is it a continuous or intermittent rating? The intermittent rating will generally be higher than the continuous rating, but the power supply won't be able to deliver the intermittent rating for a long period of time.
One thing to be careful of with Astron's, and maybe others, linear power supplies...On some Astrons, the heat sink on the back of the PS is electrically hot. If something in your system, like the shell of a coax that's connected to a radio that's connected to the power supply, touches the heat sink, you'll cause a short circuit. I've seen the sparks!