Raidmax is utter garbage, and you don't need 730W for that rig anyway, so why not put the money towards a decent PSU of smaller size?
Silverstone 80Plus 500W is a good psu iirc, for like $55.
8GB of RAM is overkill for 7750s, and the sniper series is somewhat overpriced. Any old hum-de-dum ram is probably fine, maybe like 4gb of adata for $30?
That motherboard is really good, probably too good for a 2 gpu setup. Same with the processor. Now remember you're asking as regards a mining rig, if you plan to actually use this thing, then that's a different story.
As for the cards, they kind of suck for mining, you'll get maybe 120KH? I've heard the 7790 gets about 220KH, and costs only a lil bit more, so that might be something to look at.
Breakeven? no one knows, when BTC skyrockets, it might crash LTC. Currently 200Khash will get you like $50 - $70 / mo, so... assuming nothing changes (and it will) you'd maybe breakeven in 11months? Assuming 24/7 mining, and no elec costs.