What kind of diamond engagement ring one should buy?

"A princess cut"

"A three carat diamond"

Out of a dozen or so blankings, reverts and edits, those are the only answers that didn't contain URLs, links, advertisements and pitches.

The general rule - whether we agree with it or not - is that a guy spends two months salary or wages on the engagement ring. It is to be a diamond one. She should assist in picking it out at all costs. If your budget is $2,000, then tell the person at the store $1,500 - because they are going to upsell, so will be getting you back up to just where you want to be.

Now if any wish to add to this what kind of diamond engagement ring they think one should buy, please do so, but do not put in ads or URLs, just types and kinds and colors and clarities and such that is relevent to the question.