How many megapixcels equivalent to 35 mm in quality

How many megapixels does a digital camera need to produce an 8" by
10" print equivalent in quality to what one would get from a 35 mm camera
(or for that matter a larger format) shooting a top of the run film, such
as a major brand 100-125 ASA color (or black and white) film.

The bottom line, if I replace a film camera with a digital, and want the
same quality enlargements, am I talking about the current models now
available (costing perhaps $500 to a bit over $1000), typically with
roughly 10 MP, or am I talking about something not designed for other than
professional use such as the $8000 Canon with 21 mp, or perhpas something
yet to be invented.