Miles Hecker over at The Luminous Landscape has posted two quick pieces on why field photographers really ought to make tablet PCs part of their kit. He rightly argues that the weight difference alone between a tablet and a laptop is worth the inevitable tradeoffs in performance.
For now, the software choices remain limited, though the eventual release of Lightroom 4 should improve the situation as third-party developers better integrate tablet-based apps with the Lightroom workflow. One promising example is Photosmith, which is working on an all-new version of its Lightroom plug-in.
The Lightroom community initially was quite excited about Photosmith in early 2011 because it offered the prospect of being able to dump a card's worth of photos to your iPad, where you could add keywords and tags while still in the field. Once you got back to your Lightroom-equipped main computer, you'd be able to move those photos off the iPad right into a Lightroom catalog—along with the tags.
Alas, Photosmith v1 forced you to apply those tags one photo at a time, a deal-killing time suck that caused me and others to reluctantly abandon the plug-in. To their credit, Photosmith's developers have kept, um, plugging away at reconceiving and recoding the plug-in to coincide with Lightroom 4's eventual release.
When that time comes, I'll let you know how v2 fares in the field. Like plenty of other photographers, I can't wait to leave my laptop behind for good.