Need help on building a new pc

i need to build a new pc, since its cheaper, as far as performance, and speed, compared to buying a prebuilt pc.
here are the things id be using my pc for
recording music ( im a musician myself), playing rts (real time strategy games, like homm, warcraft, starcraft, etc.) surfing the net, also do i need a sound card for recording music? typing scripts for movies which i do with my spare time
heres what i have as an idea of a build
evga gtx 260 core 216 superclocked video card
nzxt tempest case
ultra x4 1600 watt powersupply
western digital 1 tb harddrive
lite-on blu-ray combo drive
masscool thermal gel
coolmaster hyper 212 plus cpu cooler
intel core i7 930 2.8 ghz
evga x58 sli classfied mobo
all for $1972.67
with two year extended warranty on the harddrive, blu-ray combo drive, cpu, cpu cooler
OR
nzxt alpha case
evga x58 sli le mobo
everthings the same, including warranty, and the mobo has no lifetime warranty but has two year extended warranty after the 24 months of original warranty for $1837.65

1st question, are either build too much for what i need, but the question is really, are they fast enough
cuase my
2nd question, does anyone know how to build a pc for CHEAP, but not have a lag or even freeze and crash on you.
i want a pc thats reliable, with lifetime warranty on mobo and vid card, since those are the only parts that come with a lifetime warranty, and is fast on everday use, cause thats how im going to use, it everday!
so thanks for your advice if any giving. peace!

Did you take a look at the $1500 build on Tom's? It's a more balanced system than your build. http://www.tomshardware.com/review [...] ,2582.html

Why the 1600W PSU when a quality 700W PSU is enough and more efficient?