Some here will tell you to leave a couple inches.

The book I read said to get the studs as close to the block/concrete as
you can but still have them plumb and straight. Then insulate with R13
non-faced batts and staple a continuous vapor barrier on the room side
of wall.

If you have plumbing along the wall, I'd guess the choice on an
additional few inches of clearance or building soffits is entirely
yours.

The 2' access space seems handy but sure is a high price to pay to
avoid having to re-do some drywall in 20 years, no matter how big the
basement is.


-rev