If you're on a budget and can accept a "slower" lens, I think it's pretty hard to beat the Tamron 18-270 f/3.5-5.6 VC. The only reason I'm finally looking to replace mine is that I want larger apertures; I just don't get the chance to shoot much in well lit conditions
Aside from that, the Tammy's lived on my 40D for nearly a year and half now. The VC on mine appears to work way better than the IS on my 100-400L, and it's a nice, compact and light lens for general shooting. Plus, the "full" 18-270 range (28-432 35mm equivalent) is just SUPER nice.
And this lens goes for right around $500 these days; so the price is definitely right.
Is it better than the 55-250?