Hello, Im getting new home router. I can get all 3 for almost the same price. Which is the best buy? Thank you for your advices.

Get RB951G-2HnD if you need wireless (WiFi), and RB750Gr3 otherwise.

among those 951g/951ui for decent wifi(yet w/o high-gain antennas)
and 750Gr3 for decent routing performance.
450g/850gx2 is basically ~ worthless for Home usage, but may had use if you run ISP biz or something like that. (i had both antics of, wouldn't call them "terrible", they just "not up to today networking" in terms of performance)

I`m wondering since RB750Gr3 can do everything that RB450G does, why still manufacturing RB450G.