I remembered reading this in Phillip Keller's book As a Tree Grows:
Rather than learning random verses, it is well to master whole blocks of the Bible. This gives continuity and coherence to the material in mind. Here are twenty-four passages which, if mastered - one each month - at the end of only two years will have provided material that can completely transform the fabric of a Christian's life. One cannot absorb these and not grow!
1 Samuel 2:1-10
1 Corinthians 13
Who doesn't want spiritual growth???
So I started using this system, but focused primarily on chunks of Scripture. I took some from Keller's list and have added some of my own. I have also interspersed a few topical verses that I just wanted to memorize.
So far, this system hasn't been cumbersome at all. I did realize quickly that I don't memorize things as well as I used to. The good thing about this system, though, is that it builds in a lot of repetition. It's also easily tailored. My friend Carrie adds a new verse each day; I add one every other day. If I miss a day (such as through the holidays or for whatever reason), I just pick up the next day. It also doesn't require anything fancy: just some 3x5 notecards, a notebook, and a pen. (However, Carrie did give me some pretty colored pens for Christmas, which makes it even more fun!) :)
If you don't have a regular Scripture memory system, I encourage you to try this. Or find some other system (and let everyone know about it in the comments). The important thing is to continually be hiding God's Word in your heart.