That made perfect sense to me, it is my first set of power tools im going to be buying so I reckon you have just saved me a bunch of money by suggesting the 18v stuff which will cover more jobs than lower power tools.....I was also thinking of the weight difference with the bigger stuff....not that im a weakling or anything but it all contributes to the descision process.
How many drills do people actually have that they use for most day to day jobs? (impact, drill/driver, combi, hammer)
for me i would say you would want a set of 18v tools of the same manufacture using the same batterys something like :
cordless drill driver or combi drill (for screwdriving and drilling holes, combi drill is not that important if you have an sds and would add weight)
cordless sds (an 18v sds will be perfect for most fixings and small holes through walls, can also chisel/chip small jobs. use your 110v drill for major work)
cordless circular saw (a must for getting up floors, cutting timbers etc)
cordless rip saw (not as important but very handy for cutting in places that your circular cant get to, plunge cutting its great)
torch (for up lofts,under floors etc...)
radio (to help make the day go quickly and find out if theres traffic on the way home from job)
tools to consider adding at a later time when needed:
jigsaw
grinder
smaller drill driver
The most used tool will be the drill driver/combi drill, if you only have one it will need to be a top of the range one with 60-80 nm of torque. this will drill almost any hole you would wish to in wood,plastic and metals.
if i was on a limited budget i would get dewalt xr li-on followed my makita li-on. This is because they are well priced, you can get bare tools to add to your set for very cheap and the batterys are very cheap to buy extra's.