I am also in the same boat.
To be able to make the best decision, two days ago I tested Lumia 735,830 and 930 at a local store.
Lumia 930 doesn't impress me at all, it's bulkiness is a huge deal-breaker for me, and there is where the Lumia 830
surprised me! At almost the same size, the slimmer side profile gave me the feeling that it has half the depth of 930!
BUT after using Lumia 630 for 4 months, It is clear to me that my next windows phone must have OLED display, so Lumia 830 is
a no-go.
Also 930's display appeared to me less smooth than 730's display [display's hz aspect]. Which brings me to Lumia 735..
Lumia 735 in hand feels like a veery slim phone, it has great ergonomics and truly is a stunning looking device
[especially with the gray back cover] .
The display is extremely clear with perfect viewing angles from all sides of viewing. [I'm saying that because many have said that 630 has great viewing angles but apart from viewing the display from the vertical and horizontal axis, the colors are switching-inverting like hell]
Lumia 735 has the same battery performance as my Lumia 630, which means 1.5-2 days with average (normal) usage.
Now Lumia 925's processor (believe it or not) is at the same league as 735's, but is more power hungry.
It has no expendable memory (I know you don't mind) but if you ever feel the need for any reason to expand your memory or put your files on another phone/device,you are out of luck.
I have seen many reviews complaining about the slippery sides of the 925..
Also the battery life is not as good as 735's.
Lumia 925 has smaller screen with bigger boarders around the display.