I, too, answered my husband’s proposal with “Have you thought about this?” What an idiot I was. I should have said yes before he finished asking. Instead, I offered him a take-back. Cripes. Fortunately, he said, “Yes.” I answered, “Well, then, yes!”
The ring does demonstrate premeditation.
To me, “getting married” is a decision that you mutually agree upon together–the female half of the pair doesn’t have to sit there passively and wait to be invited, which is what a formal proposal is.
So since you’re not going to officially invite her to join you in a permanent partnership, you don’t need to have a ring to show her (symbolic of your financial solvency and ability to care for her, leftover from earlier non-feminist eras when the bride expected to be cared for by the husband).
Us’ns got engaged first, then we picked out our rings–plural–together, which rings then symbolized, not his deep enough pockets to be able to afford a wife, the way you have to be rich enough to afford a car, or a race horse, but our partnership together.
I got proposed to with a receipt for a ring! That episode never fails to amuse me.
I proposed to my husband without a ring 
We have matching wedding bands carved with roses, but no engagement ring.
<edit> he was a little miffed that I beat him to it, though.
Not even slightly tacky.
Not tacky at all!!
The Mr. knew I’d rather pick out my own ring and proposed with a piece of paper that said, “Voucher for one engagement ring shopping trip.”
(Of course, some doinks at work kept insisting that I wasn’t “really” engaged because I didn’t have a ring. One person even said that I needed to be “marked.” Searching frantically for a Sharpie marker to draw on my finger turned out to be a great response. :D)
Because I worked at a newspaper, my then-fiance faxed a press release to our office, complete with contact information. My boss called him up to “confirm” everything, and then intimated very strongly that it would be in his best interests to show up in person so everybody could get a look at him, and furthermore, that bringing doughnuts would gain him points.
He showed up, as ordered, with doughnuts. The boss approved.
I don’t like doughnuts, myself.
I’m fairly confident now that not having a ring during the asking won’t be a problem, and will probably be better, in fact. Now I just have to figure out what I want to do instead, and resist the urge to blurt out the question prematurely.
If I don’t chicken out, I’ll have to come back here and share the answer.
I proposed with a blowjob - is that too tacky?
It worked, btw. It’s all about sincerity.
If you ever decide to go into sales I want you on my team! You’re a closer!
And even though we ain’t got money,
I’m so in love with you honey,
Everything will bring a chain of love
And in the mornin’ when I rise
Bring a tear of joy to my eyes
And tell me everything’s going to be all right.
~Danny’s Song, Kenny Loggins.
Just thought I’d mention that.