I run pretty much nothing but premium gas in small performance engines, that includes my snowmobiles and motorcycles, but not my lawnmower. I find that it seems to make 'em run just a little bit better, start just a little bit easier and just be a bit more pleasant overall to keep around.
I also try to use good 2 stroke oil. This is one of those things that the folks over on Snomowbileforum.com will debate endlessly. I'm using Castrol GoSnow right now which seems to be a good oil, I've also used alot of Arctic Cat oil. Both are about $20/gal which I consider pretty reasonable. There are those that say the cheap stuff from Wal-Mart is fine and it probably is but I don't want to chance it.
The other thing is I buy oil from Randy at Wheels in Motion just down the road from my house. I know Randy and if I'm in a bind he'll let me work in his nice warm shop with his nice warm tools and use the compressor and air tools. Thats a real bonus that I get from giving Randy all my business. Sure I could order parts cheaper online but then I wouldn't get all the advantage working with a local shop provides.
Support your local businesses, Wal-Mart doesn't give a damn about you no matter what they say. The local guy wants you to come back and spend more so he's going to be alot more likely to treat you good and do right by you.