It's a lot of information to take in but I would first like to outline
two systems that I've ‘ended up' with (purely based on reviews and
user opinions):

Book a session at your local Richer Sounds or similar (i.e. NOT a
"high-end" audio shop) to listen to a selection of speakers. These,
and where you put them in your room, make by far the most difference.

Spend around £100 on an amp, rather less on a CD player. (Richer
sounds use the "Cambridge Audio" name now. It's not the old Cambridge
Audio stuff, but it's pretty good, and inexpensive).

Don't believe a word of what they tell you about interconnects. Go to
Maplins or your local electrical shop and buy something multi-stranded
and as thick as will go into the terminals for the speakers.

Enjoy your music.
Remember, moving your listening position a few inches makes much more
difference than changing cables. Finding the best room position for
your speakers makes much more difference than just about anything
else.