Well, I'm sure you can probably get bespoke Charvet (or what have you) buttondowns for $350+ a shirt - I think Paul Stuart's $70 buttondown is better than all of the other equivalently priced shirts I've dealt with.
The only label that doesn't produce anything I wouldn't buy is CP Company... so, Massimo Osti, but I don't think that's mainstream.
I chose Ralph Lauren, then, I guess, for Purple Label...although that clothing doesn't really seem "designed".
Just as an adjunct - your best option would be to first learn what sizes fit you correctly (good fitting clothing looks better than ill fitting expensive clothing). Then, learn a bit about makers and things like that.
After that, start looking on EBay and Bluefly for things - you'll save a surprising amount of money. I kind of split 50/50 between paying retail and buying new stuff on the 'sale' sites like EBay and Bluefly...but I look at paying retail as a luxury more...
Don't know if this has been posted before, or recently, but Hilditch and Key sells their shirts on their website for about $95 per (shipping included, minimum order of 3 shirts).
Hilditch and Key US Pricing
I really like Hilditch & Key shirts, and it'd be hard to find a comparable shirt for $100 retail, IMO.
Preppy Fusion, maybe? Most of the stuff I wear is stuff I've been wearing and people I know have been wearing for a long long time...Paul Stuart, Orvis, whatever. The rest and is slightly different: Etro, maybe conservative Dolce & Gabbana, some Ferragamo, CP Company, that sort of thing.
Okay - what sizes do you usually take in clothing?
For some reason, it surprises me that higher-fashion clothing manufacturers, like Dolce & Gabbana and Versace, make clothing in rather large sizes, like XXL. I dunno, I can't imagine who the audience for it would be, and it seems like it couldn't be profitable to produce clothing in that size.
40R, 32x32, S or M, 15.5/34
The Lacoste crocodile is the only logo I'm okay with wearing...dunno why - I hate wearing anything with a logo on it. The logo is so intrinsically tied to the idea of polo shirts that it's stopped feeling like a logo.