I swear by Marshall effects.
They're well made, small footprint, quiet, cheap, look cool, easy to use and have many features associated with higher cost units like tap tempo inputs for delay, expression inputs for chorus and blending.
Love my Guv'nor 2, I use it for a subtle overdrive in my rig. Sounds nice and smooth and compressed (whether that's good or not, who knows but it works for me). Try one!
Truckstop