Without a recent AMD GPU, it's just not worth it to generate coin. Electricity costs alone will vastly outdo the benefits.
Here is a calculator for your expected time to hit a 50BC winning block. Without the right hardware, it's probably going to be in the order of years.
I used the calculator you linked with the results of "bitcoin getdifficulty" and "bitcoin gethashespersec" and it reported a 95% probability of getting a block in 16 days and 4 hours. WTF? Even before you told me your estimate of "on the order of years", I read online that it's expected to take a few months.
What's a typical number for "bitcoin gethashespersec"? Am I pouring electricity down the drain right now? I'm turning off Bitcoin generation until I figure out what I'm doing.
ETA: I don't actually know the hardwar...
Though not yet an "official" project, Google has released a Bitcoin client. As you may remember, there were concerns here about what the government/legal reaction to Bitcoin [1] will be, and the significance of certain groups lending their support to it. EFF and SIAI accept Bitcoin donations, which helps, and this action by Google is another big step.
Previous articles: SIAI accepting Bitcoin donations, Discussion on making money with Bitcoin (Clippy warning on the latter)
[1] In short, it's an anonymous P2P crypto-currency with no transaction fees, in which new units are generated by spending computer cycles computing hashes until you find one with specific properties.