I am an AA PLT Elite member and rack up about 50,000 miles a year with them via the old fashioned bum in seat way. The perk is that I get a 100% mileage bonus which I can then turn 100k into 4 one way Buisness Class ticket from $400 fares.
On special occasions I like to fly Virgin so I carry an American Express card here in the US (as there isn't a Virgin credit card) which gathers points. I'm also lucky enough to qualify for a Platinum AMEX card so I signed up on a double points offer and get two for the price of one on many purchases. So, paying for everything from my mobile phone to petrol on my gas guzzling Audi, I amass enough miles in a year to make my Christmas flight a VS flight... well except for this year where I gave the miles to my girlfriend for an Econ to UC upgrade as early Christmas present. [:?]
But here's another tip. If your work makes you travel a lot sign up for EVERY mileage program you can. It's amazing how many points I've amassed on airlines I feel I never really travel. 20,000 on United, 10,000 on Delta, 50,000 Hilton Points, they all add up and with the advent of websites like Points.com you can build up enough points to transfer some programs into VS.
Lastly, don't just focus on airline programs and credit cards as good sources of points. Take a look at hotels, trains, etc. An example would be Marriott. I signed up for their points program (can't remember what it's called) and when I went on Holiday last year to the Carribean I stayed in one of their hotels for a week. As I wasn't getting any Marriott points but double airmiles I recieved 5,000 miles. Now, they don't support VS at the moment, but you could always put them into a program that allows transfers to VS via a site like the aforementioned points.com.
Hope this helps.
JC