Shawn Hessinger over at BootStrapMe brings to light an interesting observation from Forbes Magazine about whether or not to bootstrap your business. In short, if you can bootstrap it, you don't have to be sidetracked by the demands of raising money or give up equity in your new venture.
I happen to know from talking to the folks behind Numbr (more about them here and here) that they are bootstrapped as well. When that venture can be taken to the next level, which may not be all that far off, it will be much more profitable for the principals. They'll have more control to boot, as well.
One other important thing about bootstrapping is that if you want to change your business plan, you don't have to go attempt to explain this to someone else. You just do it. If you've taken other people's money, then you have to also deal with your investors, who may not like the new business plan and will cease funding you.