The 18-135 is another EF-S lens, meaning it would be useless on a FF body. If you want the best bang for the buck, and an excellent walk-around lens, then the Canon 24-105 F4L is really hard to beat. Has a nice range, is good and sharp with nice contrast, and can be had fairly cheap used, as it was a kit lens with the 5D MkII body for a couple years. I know it is still up there in price range, but as was suggested. Spend money on glass now before investing in expensive bodies, as bodies are throwaways, (financially), every 2-3 years, but glass will last you a lifetime if cared for correctly.
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