This is what I shoot for.
T206 - PSA 4
1941 Play Ball - PSA 6
1948....er....49 Leaf - PSA 5-7
1948 thru 1951 Bowman - PSA 7 (1951 Mantle is a 6)
1952 Bowman - PSA 8
1953 Bowman Color - PSA 8 (except for Whitey)
1953 Bowman B&W thru 1955 Bowman - PSA 7
1951 Topps Red/Blue Backs - PSA 8
1952 Topps - PSA 6
1953 thru 1956 Topps - PSA 7
1957 Topps - PSA 8
1958 thru 1959 Topps - PSA 7
1960 thru 1961 Topps - PSA 8
1962 Topps - PSA 7
1963 thru 1967 Topps - PSA 8
1968 Topps - PSA 9 (except Ryan)
1969 thru 1970 Topps - PSA 8
1971 Topps - PSA 7
1972 thru 1979 Topps - PSA 8
For subsets it varies greatly. Some, such as the 1951 Topps Team cards in PSA 5 are pricey enough. For others, such as 1959 Bazooka, authentic suits me just fine. I like cards that look nice in the holder, but I won't pay extra for "OMG, that's the best freaking card I've ever seen in my life can I give you my children and a stack o' dead presidents for it?!?!?"
