I'm with Kathy...the 18-200 is probably the recommendation I'd make of your two choices, but I'd also highly recommend considering a step up to the 18-250 from either Sony or Tamron, as it does appear in most reviews to have not only extended the zoom range but also improved the optics and increased the overall image quality. Of course, if they're out of your price range, then they're out of your price range...the 18-200 should still be a solid and very convenient all-purpose walk around lens.
I have the A300 with the 17-55 kit lens (never used), a Minolta 50mm F1.7, a Tamron 200-500, and the Sony 18-250. The 18-250 probably handles 90% of my photos, with it's excellent quality and amazing versatility, while the other two step in for those specialty shots that require those specific lenses. The 18-250 is my go-to lens for Disney trips.