Ringflash for people are quite a bit larger then the marco ringflash you attach to the lens barrel.
Also many people dont really understand the light a ring flash produce, 99% of the images in fashion/glamour wich utilitze a ring flash is prepared in makeup. Since the light is more or less flat, the modelling of the face is up the mua. So when average joe goes out and by one, the results can be and is very often dissapointing.
As for a flash meter: Its more of a preference then anything else. I would certainly not leave the house without my flashmeter if im on assigment.
Yesterday i did a shoot for fastfood company. (wonderful food yummy!) they have just signed a deal with one of the bigger retailer. so they needed a few pictures to use for comercial posters.
When time is money (wich is was for me yesterday) im glad i had my flashmeter, surely i could chimp and get the same result in the end. But with a wireless falshmeter i meter the strobes individually (the sphere retracted on the lightmeter) thus getting the ratio im after (in this case it was a 3-strobe setup)
It also helps me remember diffrent light ratios and how they will look. But as i said its more a question about a personal workflow then anything else.
Im adding stuff all the time, but when it comes to lenses and bodies i really dont need anything right now (want is another thing though lo)
Next purchase isnt all that exciting, its lightning gear(manfrotto still life table) and transportation bags. Also plan to add a skylitepanel.