This word limit is a nightmare
Remember, your kit needs to keep you warm when it's wet (the cold literally kills - you get wet, cold and you tense up, reducing control, your reactions slow and you lose concentration) and cool when it's warm (yep, overheating does the same). It needs to balance protection with comfort as being comfortable will allow you to concentrate on the road, not on the fact that your trousers don't quite fit whilst you're sat on your bike (they were fine in the shop!) and they're currently eroding your scrotum at an alarming rate. Ensuring you can feel pegs, levers and throttle grips through your boots and gloves will afford you control, but again they must protect you if you come off. Having protection to the point where you can't feel the controls increases your chance of needing that protection.
Also bear in mind that if you're not planning on using the bike in the wet, you can get non waterproof kit and pay £30 for a waterproof oversuit, saving you cash but making it inconvenient if you have to stop when it rains.
Consider a tank bag or a top box to carry your chain and other kit in as too much weight on your back when you come off really, REALLY hurts.
Bear in mind you do often get what you pay for, but if a shop starts trying to push you into buying a £450 helmet just walk out - you don't want to go anywhere where they're not advising you in your best interests. List your city and someone will be able to advise you on honest shops.
Consider the type of crashes you're likely to have - fast crashes in a track mean you're likely to need good abrasion resistance as you slippy slide but we're not looking at that, we're looking at going from 30-0 in 0.5 seconds via the floor. Impact protection is very important as is making sure you're not carrying bulky things in pockets - a mobile phone in a pocket over your chest can cause a pneumothorax if you land on it and a screwdriver in your trouser pocket could dig through your femoral artery. The initial force will rip stitching and cheap zips apart and you'll then feel the lack of abrasion resistance - check for decent stitching (you'll know the difference when you examine various priced kit) and good zips.
If you want more specific advice on individual products, you'll have to say what sort of bike you'll be riding and also if it'll be all year or just nice weather. Commuting kit needs to be of a higher spec than occasional jaunt kit, especially from the drying out side of things.