I continue to buy the old 18v versions (at pawn shops) people are all clamoring for the Li-ion, so the price of these old beasts continues to go down...
now for "occasional light around the house work" you may find the 18v too heavy, but it will not let you down... remember when the Li-ion battery dies - it is immediate... there is NO way I will ever have one without two or more batteries!!!
So with that thought, you may opt for a 12v drill, again, if you are not hung up on new - you will get a SMOKIN' deal at a pawn shop!
As far as the impact drill, yes, I did go out and buy the impact drill (again 18v so I have batteries for all my stuff - recip saw, circular saw, drill and now impact!) for the few things I have used it for, it has been priceless and I wish I would have had it earlier...
Additionally, over the past three years, I have gotten into more hand tools and I find my eggbeater much better for light-duty tasks around the house but I understand that is not true for everyone...
Last, if you do plan to buy new and you can wait - I have always found black Friday deals to be REALLY great. Lowes usually runs a drill set (drill and impact) or a combo set for a pretty good deal... not sure what HD does, and of course, you should watch for Klingspore specials too!