From a collecting perspective, there is not much more satisfying feeling than entering the last remaining cards from an almost complete checklist and watch the % Complete field of my super awesome spreadsheet change to 100%. I can then delete that set from the checklist. Unfortuately, I just wind up adding another set.
One of the master sets I am working to complete is the 2003 Donruss Diamond Kings set. I've finished the base set and am whittling away the inserts. I am pleased to say that the Evolution insert set is now done! The last one I needed was Barry Bonds, and I finally found it for a great price. This is one of those "sportflixy" sets that I am typically drawn to:
This is a fantastic checklist of HOFs, stars, roiders and... Kerry Wood.