I use QuickSilver. The best app launcher out there, has a clipboard plugin. Best of all: it's completely free, even for the system functions, unlike Alfred. Although, I have to mention Alfred also has a clipboard manager.
Jumpcut is another neat timesaver Clipboard App. It keeps a memory of up to your last100 Copy Commands in a drop down list so you can easily Paste something you Copied at an earlier time. It hasn't been updated in a while but it works great with ML and it's free.