I use a BARE Arctic one-piece 7mm suit (hoodless) with a matching 7mm hooded vest. For water temps above 60F, I use just the one-piece with a separate hood.
For Monterey I also wore the matching hooded vest. It was a bit chilly, but not so much so that it affected my dive. While the double 7mm layers would require a lot of weight, it was offset by the fact that I was diving with a steel tank (I believe it was an 85). I only needed 20 lbs in my integrated BC, the same as when I use a single 7mm with an Al 80.
The Bare Arctic suits have zippers at the ankles and wrists to make them easier to don and remove, though on my last shore dive some sand has caused one of the zippers to get stuck :11: They also have wrist/ankle seals to reduce water sloshing and thus keep you warmer.
As far as the gloves and hood, I always wear gloves as my hands get cold real easily, and as someone has pointed out CA is the land (sea?) of the thermocline so hoods are always a good idea. However, when temps were unusually warm in Catalina recently I was very tempted to omit the hood.
I too plan on more tropical diving (I was in Hawaii last March, and an April '05 trip is in the works) so there's really no alternative but to have two different suits; what's necessary in CA would be too hot for HI, and what's tolerable for HI would still be too cold for CA except in conditions we had last summer off Catalina. I have a ScubaPro 3mm one piece that I bought on closeout from a Waikiki dive shop.