Welcome to GeekHack. It appears that you already know quite a bit about our shared hobby. I think browns are a great place to start, and a nice feeling switch (some here disagree). I only have experience with Browns, but I'm building a custom keyboard with Green switches.
Prepare for your wallet to be consumed. We've got it all: Custom keyboards, Korean keyboards, custom keycaps, keycaps shaped like Iron Man's helmet with glowing eyes. Filco is arguably one of the most mod-friendly keyboards due to the sheer (comparatively) number of aftermarket parts, so you chose a good keyboard to start with for modding. Switches are a matter of personal preference, and if you find you don't like a certain switch, once you reach 60 posts, you can sell it here to another member for money to buy another keyboard (or textbooks if you need them).