not an easy one. I think you need a few drills I have a garage load of things but carry
1, lightweight cordless 18v hitachi (makita is a bit heavy)
2, 24v sds 3 function milwakee
3, corded multi drill hilti
4, core bit drill perles
for a begginer i would suggest a makita 18v
and a corded combi 3 function makita is handy cheap enough to do anything. I have cut 6 inch core bit holes.
they dont last forever and you will chop and change I'm guessing you don't have bottom less pockets. the best wat is to try some one elses and ask them. Im sure someone is going to tell you to buy a £10 grand protool, problem is when it gets nicked you cry. Protool are the dogs dangely bits though. recently bought the jigsaw but got the mayfell circ in stead of the protool/festool. I'd also look at a fein multimaster had mine for 10 years don't know how i lived without it.