Pick a place within "normal" driving distance (think about 6" of SNOW on the ground
the day you have to make the trip) that provides IN-the-STORE Service.

Example: Best Buy has the "Geek Squad" inside their larger stores ...
the "Geeks" may not be rocket scientists, but they know more about 'puters than you & I do!

Don't overlook a LOCAL Computer shop - as long as it's neat, clean, and the Head Tech
looks like he's taken a bath/shower within the last month.

Select a Service Provider; THEN talk to their Sales Department.
Buy what the Service Guys are authorized to service & repair.

Ask to talk to the Computer Dept Sales MANAGER ... feel him/her out for who's the
most experienced (longest employed) sales person. Come back at another time if
the lead sales person isn't working when you're there ...
you DON'T want to be sold by the kid with a week's experience!

Ask to see last week's, last month's, last year's models - they'll be the ones on SALE,
and chances are you'll never know the difference (other than $$$) between
the "old one" and the "new one".

As others have said - AVOID a unit that runs "Vista" --- too new to trust.
INSIST that you want the machine loaded with Winderz "XP" - accept no substitutes!