well it's like this,
nvidia gpu-s really suck at mining. you can buy some ATI radeon hd7950/7970/7970 an mine some LTC for example and change them to BTC. small steps but it's something.
you are right about that, there is no point mining unless you buy a dedicated mining gear.
btc difficulty is so high right now that with 200GH miner you will earn 0.06btc/day and with every diff jump you will earn less and less.
so 200gh is minimum to start right now, everything below that is worthless.
this is good miner for fair price
https://bitcointalk.org/index.php?topic=379819.0so think about it.
about electricity,
there is some point in mining when miner will suck more electricity than he can earn btc/$ and then you sell it on ebay usually for more than you pay for it.
till then you will earn a nice amount of btc.