64-bit Issues?

[William Ahern]

Can anybody give a summary of manifest or potential 64-bit issues? I spotted
some posts which hint at such issues.

I anticipate porting my current development project to x86-64 soon, and I'd
like to know what to look out for. I'm in full development mode, so I'm
fully prepared to bust out Valgrind, hunt down the bugs, and submit patches.
But I'm also not in the mood for extraordinary surprises ;)