James - Ive had Sky+ since August 06 and quite frankly, its a superb device.
I did a lot of research on these forums beforehand so here's a few tips for you (apologies in advance if you know any of this already..)
The box you get will be 160gb box - however - only 80gb is for your own use (which equates to 40 hrs of telly). The other 80gb is reserved for Sky Anytime. There's currently no way of altering this arrangement. C'est la vie.
The biggest cause of Sky+ boxes failing is overheating...therefore don't place any other kit on top of it, also, ensure air can flow around it on both sides. A flat stable surface is also your best best.
Instant Rewind - turn it off if you don't use it. When this function is ON it basically means your box is recording **all the time**. Switching it off saves a lot of wear and tear. You can still "pause live telly" by pressing the pause button on the remote (eg when watching the footy and the doorbell rings).
Finally, use a decent scart lead (not neccessarily expensive) and ensure the picture settings are switched to 'RGB' and the scart is plugged into an RGB-capable socket on your TV.
I've followed all these tips since day 1 - excellent picture quality and not one glitch !!
Happy viewing.
One more thing - I've also de-activated Sky Anytime - there was never anything of interest to me, so again, turning the function off saves more unnecessary wear and tear.