Specific types of businesses can use Bitcoin to either reduce processing costs/fees, or improve the ease of service. It also avoids the need for the user to provide credit card or other personal details, which a lot of people are wary of doing.
Satoshidice is a good example. It's very easy to make a bet, as it just requires sending bitcoins to a particular address.
coindl.com is another example, which lets you purchase music (and more) with bitcoins. There's no need to create an account; just make your payment and download the files.
High foreign exchange fees can be reduced by using Bitcoin exchanges to make an intermediate step through Bitcoin (convert currency1 to bitcoin and then bitcoin to currency2). This can reduce an 8% (or higher loss) to as little as 1%. This might not be the kind of spending you envisage, but it's nonetheless beneficial to the user.
You're probably best to avoid trying to receive bitcoins in return for things like sysadmin work. If you end goal is to get bitcoins, you will likely get more of them by earning cash then just converting some or all of it to bitcoins.
What I'm saying is that rather than going to lots of effort to use Bitcoin for something that's difficult to achieve, you're better off using Bitcoin for what it's great for.
1Plenty of people seem to be spending them on Silk Road – None – 2013-02-18T22:15:02.627
Have a look at the activity of the Tipping Bot on Reddit. You'll find that many people are generous with their bitcoins.
– Gary Rowe – 2013-02-19T10:46:21.857most of my customers use bitcoin to pay me, and more than 50 % of my income in now related with bitcoin, but sorry i wont give you my customers, wish you to find your own customers ! – neofutur – 2013-08-26T19:01:33.767