metal_xxx wroteCW is pretty mediocre yeah... But I find some songs pretty cool once in a while. I will get into the ones I've bought now, and probably get the rest later for collection's sake.
Even if you don't like CW you should still get Youthanasia. I didn't like it at first (bought it the same day I bought RiP) but it grew on me, and now I love it.
Also the 2 new ones aren't that bad, nothing special but still worth getting.
Back in the Day is such a kick ass song.
EDIT: get Hidden Treasures if you can, so many good songs on that. It also has my first ever Megadeth song, 99 Ways to Die.