for those little jobs you mention, I reckon an 18v cordless combi, with ability to switch on hammer action, and a clutch for screws, will do you.
Less than 18v will be too weedy, more will be too heavy.
Look for one with a spare battery.
Ownbrand from Wickes or Aldi will be adequate. look for a 2-year guarantee and buy it just before you start getting busy. They have special offers at, and just before, bank holidays.
A corded drill of equivalent power will be cheaper and last longer, but not as versatile. Useful to have both, and if you need a bigger drill, make it a corded one.
If you can get a kit with a hard plastic case and a starter set of HSS and Masonry bits, it will be handy and save you losing them. You will break the smaller sizes of bit, and wear out a few of the common sizes. Get replacements on ebay in quantity in just the sizes you need. Small sets of bits in the shops are expensive.
Sets of screwdriver tips are cheap and wear out quickly.