We don't typically have particularly high-level characters, so my highest was somewhere in the 40s, from both a dwarf druid/nature's warrior and a githzerai monk/psychic warrior.
The dwarf could regularly get into the 40s with an attack roll, since his buffed attack bonus was something along the lines of +25. This was around 12th level.
The githzerai monk had a Tumble check of about the same, at 10th. This was before the group started using opposed Tumble checks, so I never actually bothered to roll it, since the check was high enough that I could do anything in the Tumble description without rolling.