If I am taking a long trip, and I could only bring one lens with me, this is it. While it clearly suffers in low light, in my book it is probably the best all round, general purpose lens available. While it won’t give you the same quality as Canon L lenses, its versatility is hard to beat! (Pretty light too!). There are many arguments that can be made that this should be your first lens as well, instead of going with an 18-55 kit lens.

Tamron has regular rebate offers that usually will bring it down into the $350 range. With a 6 year warranty, wow, hard to beat that value.