I like! So what about the empty head room in the 5 gal carboy? Do I need to do the primary in the bucket & transfer after the initial krausen explosion into a 3 gal carboy or is that air space bad in the 5 gal.?
No need to transfer anything until you're ready to bottle. Unless you are doing some sort of a special step, such as adding a pound of crushed blueberries or something, there's no reason at all to rack (transfer) the beer to a secondary fermenter. The risk of autolysis (yeast die off producing off flavors) isn't really a concern for homebrewers, and I seriously doubt it manifests at all in small batches fermenting in the primary for less than a month or two.
There's no reason you can't just use buckets. I use the six gallon "better" buckets for fermenting, which you can find at homebrew shops. The only trick with them is, you need to be careful NOT TO SCRATCH the interior of the buckets with anything abrasive. Don't use anything harsher than a paper towel to clean them out, or the scratches will harbor bacteria which can infect your beer. Most homebrew shops that carry the buckets will also have sterile bucket liners, which can make cleanup a snap. Just install the liner before your brew session, and when the fermentation is all over and you've transferred your beer to a bottling bucket, just remove the liner and toss out everything (including the remaining trub at the bottom).
So, when I brew up a batch of anything, I put the wort in a sanitized bucket with a few drops of fermcap in it, seal it up and add a bubble lock, and let the whole bucket ferment in my temperature controlled converted drop freezer. I set my external temperature control towards the bottom end of what the yeast will tolerate (in it's preferred fermentation temperature range) and just forget about the bucket for two or three weeks depending on the beer. Then, i'll take some gravity readings with my hydrometer until the readings are consecutive for 2-3 days, then bottle/keg it up with a little priming sugar added to the bottling bucket.
Generally, it takes about a week to ten days at room temperatures to carbonate up, and it's usually drinkable after two weeks in the bottle unless it's a very high gravity beer, which benefits from additional conditioning before consumption.
IMHO, glass and plastic carboys are expensive, heavy and difficult to work with and clean. Scraping the trub out of a glass carboy is easier said than done if it's dried and caked in.