I decided not to purchase stationery when I moved and got only new business cards. I do have shipping labels printed with my name & address that I can also use on tax folders, colors do match the folders so it looks nice. I don't use these regularly on folders for all returns, only oddball returns that I haven't printed out labels for at the beginning of the season.
For letterhead, I created that as a template in MS-Word. I usually print on plain paper, but if you want it to be nicer without engraved stationery, you could buy heavier weight bond if you think the recipient notices or cares. No preprinted envelopes either. They are either run through my printer, again a template, or I use clear Avery address labels using the same font as the letterhead. I use these on a variety of envelopes including small return envelopes that go with invoices or balance due reminders.
I guess it depends on how much your image depends on these, and how much your clients would notice or care. Mine don't care, and the template works better for anyone that gets the correspondence by pdf attachment rather than snail mail.
Sorry for the derail from the Efin addy change, and if this portion gets lots of responses,I may move to its own topic.