Use this calculator to see if it's worth it.
http://mining.thegenesisblock.comAlso take into account how long it'll take to get to you and setting it up to mine.
I dumped $7k into building my rigs. I would've made more if I just bought $7k worth of coins. Plus my electricity bills are $3k per quarter. So yeah, I'd buy coins instead.
Hope that helps. =)
you gave no consideration for any real potential loss of btc
for example if the money was in Mt Gox, or BitInstant
not to mention if it was up it too high like those who invested in btc at anything over 900, the money is essentially trapped, that could eat away at you.