I'm a big fan of Cascade 220. While the price per ball is higher (you can find it really cheap at
Webs) you get more yardage than Lion wool, so it's overall a great deal. And they have sooo many colors available it just makes you alll happy with the possibilities. Be careful though, don't accidentally get the Cascade 220 Superwash - it won't felt. I've used it before and I've found that single-stranded it felts to about 70% its original size (but that will vary depending on your gauge).
Happy Knitting!