I spent money on a good lens, I don't usually check if my shots are focused or not.
The RGB histogram is quite useful though, but for advanced users I'll say..
Heh As for flash, get the Sigma Super DG 500.. It's about $375 new.. It's good. Very good. Much better than the $500 430EX.
The 75-300 isn't worth the $300.. It's a really really bad lens.
IMHO don't worry about the 10MP. it's just going to kill your harddisk space. As well as your computer when you do processing eventually. You're not going to spend $20 per photo to print at A3 size for all your photos ya? Do you plan to spend another $600 to upgrade your computer?
As it is, 8MP is an over-kill for you. Don't worry about "future proofing" your camera. Just for your info, even 6MP is an over kill for stuff like Straits Times, most magazines, etc.
Best to get a 2nd hand 350D from the forum.. get yourself a complete system before you worry about the body again.