From the answers given, the 1000D doesn’t seem to lose a lot of core external controls versus the 500D/550D, but there are a few practical handling differences.

The main missing feature mentioned is spot metering, which can be useful for portraits and tricky lighting. If you don’t have it, you can usually work around that by taking a test shot and checking the histogram.

Other differences noted were:

• no wireless remote support (but a cable release is still an option)
• a slightly smaller viewfinder
• no proximity sensor to turn off the rear LCD when you raise the camera to your eye
• a lower-grade rear LCD

The other commonly cited differences are not really control-related: lower high-ISO capability and no movie mode.

So if your use is mostly landscapes and portraits, the 1000D should still be workable. The strongest reasons to step up would be if you value spot metering, a better finder/LCD experience, or the convenience features above. Otherwise, there’s no indication here of a major control-layout limitation that makes the 1000D unsuitable for general photography.