I've always used 250W MH. Mostly because when I set up the tank I did some research which indicated that 250W was the way to go if I went metal halides. I wasn't sure what I was going to do but found a smokin deal in the buy and sell in Vancouver. The setup I bought consisted of a DIY hood with H37 ballasts which only run Iwasaki bulbs. As I hadn't had a lot of experience with halides, the "pee yellow" was fine with me
I stuck with those bulbs for 4 years and only had to change them out a couple of times during those 4 years (I think I got worried at about 18 months or so). I supplemented them with 2x40W NO actinics at the time. Eventually I switched out the NO actinics to an Icecap VHO ballast and ran 2x110W with the Iwasakis because I was getting tired of the yellow but not enough to get new ballasts (DIY electrical scares me sometimes).
Last year I switched over to M59 ballasts (I sucked it up on the electrical issue, it was easier than I thought!) as they could run pretty much any bulb I wanted. I immediately bought a set of ushio bulbs which looked the best to me when compared with a few other types of bulbs. So far I've tried the Reeflux 10K bulb (made my tank look pink, it was weird) and XM 10K bulbs (more yellowy than the ushio) and have stuck with the Ushio for now (until I try something else or something else goes on sale
).
Pretty happy with my setup, only thing I would change at this point is to go with 250W HQI ballasts if I managed to find a good deal on them, then I'd probably think about going DE someday.