You know the SU 3.0 isn't a singlespeed right?

I'm disappointed to see that Trek removed the prices from their website.

I'd agree that if you don't need a bunch of gears, don't buy them. I don't personally like flatbar bikes, but if you do, the Soho is a solid choice. Yes, there are other options out there for less money, but they likely won't have the resale value of the Trek. Personally, I can't get over the ugly welds on the Swobo bikes, although it's purely aesthetic.

Personally, I'd go with the Salsa Caseroll singlespeed, but then again, I prefer drop bars and don't have to deal with the theft problem you'll be facing. Speaking of theft, do you have a safe place to store it? The Trek could be quite the target.