Hard to choose......
Megadeth-Rust In Peace...autographed by the band in 1991 on the Rust tour
Pantera- Far beyond Driven limited edition double vinyl.... autographed on the FBY tour 1994 i think...
Carcass-Surgical steel limited edition deluxe box set 1/100 vinyl/cd/poster/certificate/medical box/patch/booklet...each item autographed....pretty rare piece.
Have heaps more autographed...but theyre the most valuable to me.