815 boards don't need RDRAM, in fact they use just regular old SDRAM.
If that's a hang up for you, I'd go with the 815, as it allows the AGP dividing options needed to overclock or run that 933 at the 133Mhz FSB.
I love the BE6-2 boards though, great boards.
If you want to try the 815E boards, get an ASUS CUSL2/CUSL2-C. For features, they're better than BX boards, however they are just a wee bit slower.