Recorded all of The Essence Of Winter with D standard tuning and have stuck with it ever since.

I play mostly in standard or in half step down, but only on my acoustics. On elektryc I play mostly in Drop C, but there You have to use thicker strings, like these
https://musicsquare.co.uk/106038_D8242Addario-EXL145-Nickel-Wound-Heavy-Plain-3rd-1254-Electric-Guitar-Strings.html
https://www.sweetwater.com/store/detail/DMS2555--dean-markley-2555-blue-steel-electric-guitar-strings-012-054-jazz

Standard for quite a while but now I'm playing in C. I dislike drop tunings.

Yeah Drop D or standard for us. I think if I start struggling for a bit of inspiration ill mess around more.

I used to play in either drop-B or C# standard when I was in a band (Machine Head was my biggest influence at the time). Now I have a 7-string to play in E-standard, drop-D, B-standard or drop-A (or any half/full steps down on any of those). A 7-string is the most versatile for different tunings IMO (obviously without a floyd rose as much as I enjoy them!).