LC Power MIDI 648B LC420H 420W...so this means one combo case+ lc psu 420w ? cause if it is forget about the 660 gtx ti, cause that psu is crap only the 7750 will do for that or which will be better spend in a separately better case and buy a decent psu (corsair,xfx,antec,seasonic 450w-500w) and then think about the 660 gtx or 7870 amd.
I would strongly recommend purchasing a SSD to use as a boot drive. This will not increase performance gaming wise (it will not increase fps although it will speed up load times), but it will greatly speed up your system starts, shutdowns, and native OS operations.
Below is a SSD I recently installed in a HTPC I built for my old man. I do not know if it's because I paired it with a microATX motherboard, but this thing loads Windows 7 in 5-7 seconds.
OCZ 60GB Vertex Plus R2 Series SATA II 2.5-inch SSD
Plus, if you get a large enough SSD you can load a few of your favorite games on there. I had Battlefield 3 installed on my SSD and the maps would load much faster.
Just a warning to the guy don't buy anything yet because that psu doesn't has any pci-e connector 6-Pin or x 6+2-Pin, it is really a crappy type of office pc low psu only the 7750 which doesn't need external power will do but still is risky so you have to ditch that case+psu and buy like i said a decent psu, then within your budget try the 7850 or if it is still within the budget the 7870.
And see if there is any seagate 1tb 7200rpm in your area the cheapest 1tb hdds 7200rpm nowadays.