A few additional (and some repetitive) thoughts, since we just went through this:
1. Definitely consider the location and spread of regular 120v lighting (GFCI protected, of course). The 12v is nice for path delineation, but doesn't do much to really light the area, at least not without specialty fixtures. Our pool is a little smaller than yours. We opted to have the electrician rough out four lamp post positions for us (12/2 UB cable into code-required conduit). I poured the footers and installed the posts and fixtures myself. We use just 40 watt bulbs (we're not trying to read the phonebook out there) which is plenty bright for area light and looks great.
2. Definitely agree with all the comments on outlets. You really can't have too many. Think about not only where you might like to plug in a radio or light, but also where you might like to have an outdoor kitchen or fire pit in the future. Even if you just have him drop conduit in from your equipment pad (or wherever you have a panel), it will make your life so much easier.
3. Think about low voltage lighting for the future and get that cable in or at least put conduits in where you might need to pull under deck or sidewalks int he future. Having pre-laid conduit under our concrete path has already saved me a bunch of time.
4. Speakers are key if you like music and media. The best solution I've found (and most economical) is to use the very same cable for 12v lighting for the speaker runs. It is typically 14 or 12 gauge (12 is better for long runs) and is meant for direct burial. It's a lot less expensive than specialty speaker cable or conduit.
5. Think about phone, network and TV from the house if you're into that sort of thing, or if you are building a pool house. I was able to find a direct burial multi-cable (2 x Cat5e and 2 x RG-6 coax) for a reasonable price online. While it can be put right in the ground, I had the electrician put it in a conduit run from the house to the equipment pad, just for longer-lasting protection (since our soil is quite rocky in areas).
6. If he (or she) is pulling down power from the house to a subpanel at your equipment pad, it never hurts (except in the wallet) to up-size the breaker to give you a bit more expansion room in the future. For reference, we pulled 60A to the subpanel, which feeds a VS3050 pump, a booster pump, SWG, 2xIntellibrites, 4x120v lights and a number of outlets. We'll add a pool house later this year.