dvd
I never thought compatibility was a huge issue, unless you plan to lend your recordings to others, and even then most of the more modern players play both dash (minus) and plus formats. The most incompatible is DVD Ram - but also the best in terms of features - for "pausing live tv" and starting to watch a film you are recording before it's actually finished. For this reason I purchased a Dvd recorder that writes to DVD-R, DVD-RW and also DVD-Ram which I use most often for the above reasons. Bear in mind that RAM incompatibility is irrelevant if it's only you thats using it!