Hi binky
I cook a lot and have tried and gathered all kinds of pots and pans.
Personally I'm not an advocate of buying into sets as although they come up cheaper than individual items there are always some you use and some you don't. So my first tip is to think about exactly what you need.
You also need to think about the heat source you use and whether it's only you using them (especially for non-stick) e.g. if you have an induction hob you need stainless steel.
This is what I find I use most and why.
le Crueset plain base enameled large casserole dish
le Crueset buffet casserole - lidded but wide and shallow
small pan with a lip for sauces and gravies
larger pan for rice and similar
massive stainless steel stock pot
steamer pan for vegetables
small frying pan for omelettes and little jobs
large frying pan
very large sauté pan which doubles as a kind of wok
So think about what you cook and how and then you can look at options.
Some of my pans are from the Judge Vista non-stick draining range and they've been excellent for value and for performance. The non stick has held up really well over the years but I am very protective of them, no metal implements and I handwash them. Woebetide anyone who approaches them with a metal spoon 
If that range interests you use a search engine as lots of places sell them and there are sale and special offers on frequently, which is when I buy. You don't need to pay full price.
Chasseur is a good alternative to le crueset and Lakeland sell cast iron cookware too but I don't know the quality. I can vouch that ours are virtually 'lifetime' purchases, so actually work out cheap in the long run.
If you do look for alternative makes of cast iron be careful, I saw some on an offer in Tesco but they were already chipped from being on display, which is not a good indication of value.
Hope all that's food for thought 