There is some utter nonsense on Answers!
If you cancel your Sky subscription, the Sky+ box will revert back to being freesatfromsky http://www.freesatfromsky.co.uk You will lose the recording facility of your Sky+ box.
However, you can cancel your Sky subscription but still pay Sky £10 per month for ONLY the recording facilities. So you can use it like now, but with none of the extra Sky channels.
In other words you will have freesatfromsky plus recording facilities.
If you do not wish to continue with Sky at all, you can swap to freesat http://www.freesat.co.uk which uses the same dish and cables, but you will need a freesat receiver and there is no Channel 5 on freesat yet. Humax are launching a freesat HD PVR the Humax FOXSAT-HDR.
If you still have an aerial and can receive Freeview, you can get something like the Humax 9200T PVR and plug that into your aerial and record two things at once, just like Sky+.
Remember that the point of Sky+, freesat PVRs and Freeview PVRs is that they have an 8 day EPG, without an EPG you will be looking through magazine listings and setting manual recordings all the time, a complete ball-ache!