While thinking about the various personal / open source projects I’d like to do in the future, I always get somewhat frustrated in wanting to take advantage of new stuff, like the OO features of PHP 5 or the vast amount of cool new stuff in MySQL 5, which are too numerous to list here.
Although these things can be very useful and result in better performing and easier to maintain applications, they are also not available on most Linux hosting services yet, which is the whole reason I started doing PHP development in the first place.
Oh, well. I think I may go for it anyway on some projects that are either not for public release, or for very limited vertical market type systems (like a grade tracking program for schools that I’m planning). All my WordPress stuff will stay strictly with the widely available versions, though.