Hi Sam,
Welcome back to this wonderful hobby/obsession of ours.
I do not know whether or not you have some astro-imaging experience; if you are just getting started with astrophotography for the first time, I would highly recommend getting a small refracting telescope (a triplet) with a quality automated focuser and with f-ratio around f/5 to f/6, and match it with a camera that would give you around 2-3 arcseconds per pixel, ideally with a dedicated OAG and all of that on the best mount you can buy.
In the end it almost entirely depends on your budget. Larger telescopes are great and almost everyone in here would love a larger one than they currently own, but unfortunately larger telescopes require larger mounts and more accurate guiding, larger CCDs, larger filters, larger correctors, larger focusers... = more $$$
There have been some outstanding astro-images presented here on IIS taken with 3-4" telescopes, so unless you really want to image galaxies, starting with a smaller telescope may be just easier = more fun.
Just my two cents