'Ere I'm not an expert y'know. Others may agree or disagree with my choice.
This is what I wear from head to toe.
Premier off road helmet, Scott goggles with double glazed lens.
Sometimes a Buffy thingy.
Helly Henson fast wicking base layer.
Plastic Axo chest and back protection. (May upgrade to a Knox back protector whilst keeping chest protector).
Rhino jacket with lining removed, fitted with shoulder, elbow and back armour. (Any cheap waterproof jacket will do, some use expensive Gortex Enduro but Gortex won't breath when it's dirty.
Many use Sinisalo jacket and matching trousers).
Sinisalo gloves, one pair of summer and 2 pairs of winter (they are not waterproof as they claim and lining pulls out making it a barsteward to put back on so a warm dry spare pair makes sense).
Hein Gericke Rallye pants with Hiprotech armour in hips, and knees. (many use moto X pants).
Knee/shin guards.
Ex army but buy them new?? gortex overtrousers (brilliant at £30)
Sidi off road boots, but I used to wear Sidi Courier as both on/off road boots untill the bike landed on my foot and broke it.
Ex army gortex boot liners.
Anne Sommers split crotch panties oh sorry I've finished now.
I try not to buy anything because of how it looks but because it works and is cheap without compromising safety. Expensive boots are a must have.
As for bikes, well it's a sweet shop out there so be wary of buying anything too powerful or racey.
XR 200 is great to get back into the sport in fact some good riders use them.
XR 400 is a great bike, better for situations where you really do need the extra grunt, also better on the road.
XR 250 is what Johnny Boxer and I prefer, although my new one is now a 280 which for me is about right. You can get them with electric start now.
Yamaha Serow 225 with electric start has low seat height..
There are loads of other bike. out there some with electric start, remember that 2 strokes have little engine braking although start easily and some have a 'lively' power delivery, although Honda CRM 250 with a powervalve is good.
But I would stay with something as simple, light and reliable as possible.
I have to admit that as for actually having fun, your old XR 200 will give £10 000 worth of GS more than a run for it's money in the winter.
Hope that helps
Tim