Get a second gen SV or SVS and never look back. My '05 always gets 50+ mpg and they are as reliable as a stone.
If I were in your shoes I might hold off a little while and see how the Gladius fits you. At 5'7" the lower seat might work better and I think it's a pretty cool looking bike. For the SVS you can put some grip heaters on, hand guards and a tall wind screen and you have exactly what you are looking for in a proven motorcycle, rain or shine. If you want to add hard bags or...you name it, there are great mods for the SV.
The EX500 and and 550e....come on, not even close and hardly any better on gas.
Get on Craigs List and you will find a bunch of nearly perfect SV's with low miles in no time.
I don't think they make a better budget bike than the SV. BTW the ninja 650 has better comfort, wind protection and lower seat. I still like the SV better because of perfomance, quality, and availability of everything you will ever need.