For reason both economical and practical, I would strongly recommend the LINE 6 M13 or M9 effects processors. My reasons for being fairly adamant about these pedals is simply that they are very practical and don't have all the extra stuff that tends to take over other processors. They are simply effects pedals, with no amp modeling or anything else to get between you and your amp. They are "true bypass" units, and LINE 6 really does a great job of making great sounding effects into an economical package.

The M13 is the larger version with a bit more options for saving settings, etc. The M9 is the smaller version with the same great sounds but a few less options. Either will give you what you want. That is my recommendation.

Check out the units at the links below:
http://line6.com/m13/
http://line6.com/m9/