Dean,
Since anything around an antenna affects/distorts the radiation
pattern to some extent, and since a dipole's radiation pattern is
sort of directional (depending on a lot of things), the usual vertical
antenna, being 'omnidirectional' would mean that the distortion
probably won't mean a 'null' somewhere in the house. (Wonder if I
could make that sentence a little bit longer??) That 'donut' radiation
pattern is the 'ideal', not what actually happens in most cases.
(There's not really a hole in the middle either.) Which would be
'beter' in your situation? Beats me. You might try it ans see, but
have the vertical antenna just in case...
'Doc