A handheld shower nozzle. These can help you save water as they can target that sudsy area more efficiently. Also, you can set the whole thing up so that when the handheld is on, the overhead is off, with a third option to turn them both off for what my grandpa called "a Navy shower" (which saves the most water).
The main thing on my wish list is a handheld attachement to the shower, but I already have a shower/tub diverter, and I can't find a three-way diverter! do you have special insight into this problem Becky?
I could live without the rest, including the vast closets. If I had a closet that size I'd rent it out!
Electrical outlet for hand-held steamer.
Big splurge: pants presser.
Specialized storage for scarves, belts, handbags.
In the bathroom: storage for a rolling laundry hamper.
Window and/or skylight for natural light which doesn't require turning on a light every time you enter.
Wall-mounted, lighted make-up/shaving mirror.
The other neat thing you can do in your kitchen is to designate a "coffee cupboard". We did a sliding shelf with an outlet in the back of the cupboard to plug in the coffee maker and had enough room for coffee cups, sugar, extra coffee, & filters all in one place! Pull the shelf out while coffee is brewing (we also had the door of the cupboard be able to push back into the side so it isn't sticking out. Everyone loves this cupboard!
Rather than a towel warmer drawer the inexpensive alternative is to put a small microwave in your dressing area (works well with a morning kitchen), then put a bit of water on your towel and fire up the wave. I know it is not as cool as a dedicated towel warming drawer but the results can be pretty close to the same.