Been looking myself recently, and as far as I can see the Humax HDR Fox T2 1Tb is the best box at the minute. Since the new YouView one came out, (which has catchup TV but is more expensive, 500Gb, removes streaming capabilities, and seems to have some issues for use as a PVR from reviews), the prices have dropped a bit, (1Tb about £250). Though you might want the catchup TV access.
Having used a Fox HD (no R - sinlge tuner version) T2 it is very easy to use, the GUI is instantly reponsive, (which my SD Sagem for all its other charms isn't), the HD pictures are great, and the upscaling seems very good and a cut above the norm, (better than the Sagem and than my Samsung TV; haven't pitted it against my projector yet). Plus can stream video files from the network or hard disk, export recording, and with custom firmware the HDR will allow remote operations from a web front end such as scheduling recordings.
The Tvonics recorders are suposed to be of a similar quality as a PVR, and the 500gb HDR500 can be had for about £114 now they've gone bust, but for the sake of possibly needing the Humax features and maybe future firmware fixes or guarantees issues, and with half the storage, I'd perhaps avoid it.
Hope what I've found out in recent investigations helps. I moved my SD Sagem into another room, and thought I could get away without dual recording in my main room, (the HD fox does sinlge recording with an external drive), but I can't. I've decided to go with a HDR Fox, but I have the cathup Tv on another device. If I didn't, would be a closer call.