For my UK flying I have been using UK2000 VFR Photographic Scenery Generation X, with Treescapes and the demo version of VFR Airfields (which fortunately includes Wellesbourne). Judging by Wellesbourne the airfields are excellent in terms of accuracy.
GenX is the first photoreal scenery I've used and I have mixed feelings. Before buying it I read a quote saying that above 800 feet it looks amazingly realistic.
I have to disagree with this. For me, at anything under 2000 it looks very 2D and just like what it is: a big photo. This makes take-off and landing a little disappointing.
However, at above 2000 ft it looks great, although the shadows from the trees can be a little jarring at times. It's particularly good with poor weather and low visibility.
Treescapes is a great product and helps enormously, positioning thousands of trees to give the landscape a more 3D feel, and mitigating the shadow problem to some extent by plonking 3D trees and woods on top of their flat photo texture.
Landclass accuracy seems good too, with the roads, railways and rivers I'm familiar with all in the right places.
But I don't have to limit my virtual flying to Blighty. Two of the great advantages FSX has over real world aviation is that you get to fly in aeroplanes and to places you would never get a chance to experience in RL.
In FSX I enjoy bush flying around Seattle, Canada and Alaska, and a while back I installed OrbX's free demo of their excellent FTX Pacific NW product.
I was very impressed, so this week I took the plunge and installed the full version, together with a couple of their free add-on airports.
After a quick hop from Vashon Island to Seattle-Tacoma and a buzz around Bowerman I was blown away.
For me, this is far better than photoreal scenery, with fantastic textures, buildings and trees right down to the moment your wheels hit the ground.
OrbX offer most of Australia and New Zealand, and a large amount of north western North America.
I would recommend the UK2000 products, but for me OrbX is streets ahead.