Reinstalling FSX - what addons are a must?

HiI've just built a new pc, and in the process of doing a complete fresh setup of FSX and my addons. However over the years I have collected all sorts of addons, with regards to mesh edits, landclass fixes, various global sceneries, and texture tweaks. In that time some of them have probably been superseeded by better products etc. So I want to put the right things back on.So in your opionions what are the must addon products freeware edits or payware that I should put back onto my system?Of course I'm already adding all my aircraft etc, will be installing latest version of REX, my Horizon UK photo scenery, and all my individual airport sceneries from around the world. But what about GEX/UTX are they still worth being put back on? I have uscanada and europe. Are there better terrain mesh now for the world? better landclass edits?What do you think are the must have addons?