thanks everyone! I am so happy with my budget...actually SHOCKED when my bf told me how much he is willing to spend. thank you everyone for all the suggestions! I definitely don't know much brands other than the ones I mentioned. I want superior workmanship and I'm sure I can get that at places other than Tiffany and Cartier.
THough I do like the idea of a custom made thing (and I will probably consider that as a top choice) I do like the idea of having a name-brand ring though. It's a girly dream I've always had....
Out of all the brands I mentioned, which one would be the best investment?
If one is referring to pecuniary value after the ring is worn, no ring with the price of $20,000 is an investment piece whether it is Cartier or Tiffany & Co. because it's just not big enough and not clear enough: if I put my 1.3 D/IF from Tiffany on eBay, it will have lost $30,000 from its value after less than a year, LOL! The reason? Why would anybody want a used engagement ring especially when it has been on the hand of a divorced woman (BTW, I'm not married yet, LOL) and I am aware that at that price I can have a 5 carat ring from an 'independent' jeweller.
So I am not going to argue with every lady here that Cartier and Tiffany does not rip you off (because I even admitted to it in older thread whilst giving you the price of a 1 D/IF with Cartier being seriously expensive and not including the platinum price) but I will tell you why you want a brand name ring.
There is this innate (and undeniable) feeling you get have a brand name ring (or any piece of jewellery). Imagine when it's nice and cosy in the evening and you sit down in front of your dressing table, then you open your drawer and take out your Cartier red box or a stack of them. You get this sense of 'yes, I've made it' LOL when you start shifting through the stack.
I am going to continue with something equally irrational because I am usually a bit spaced out


Given that you have started off with the two names of Cartier and Tiffany, LOL and admitted of the girly dream, go for the Cartier or Tiffany ring! When you have one of them on, you will start twisting it around your finger like mad (I do anyway, LOL) because you know you've got the ring that you truly want!