I've never owned a streetbike and I want a cruiser. I'm 35 yrs old, 5'8" and 180lbs. I did off-road for years but that was years ago and apples and oranges compared to street bikes. I had it narrowed down to a C50 or C50t but I keep hearing people say start smaller. I don't want to jump into an 805CC when a 598CC will do the job. My needs...a daily commuter with highway and city driving, and the random trip w/ the wife to the NC mountains or wherever but no extended trips. But I don't want to get a VLX DLX 600 and want something bigger in 6-12 months. I know a 600 will meet the commuter needs but on the mountain or 2-up rides is my concern. And if you add bags, for travel, I would think it would hamper the problem more. I will be taking the motorcycle safety class. Thank you all in advance for your feedback, opinions and insight.  

My first street bike years ago was a Kawasaki kz1000.
There is no reason to start with a small bike if you know you will be upgrading in a short time.
Most big bikes come with a lowrider seat option anyway.
I would go and sit on some bikes and see which one fits you the best.  

Take the course!!! Sorry, puts away soapbox.

When you are comparing 650's to 8/900's (except for the Savage/M42) the weight of the Star isn't much different than the Vulcans/ C50.

If you are looking at mountains AND 2 up, you may need the 800-900. You can do it on the 600, and keeping up good speed, you just have to downshift early and often.

I'd almost recommend buy the C50, but, buy an old beater too. Since you've ridden before, you should be comfortable in a month. Then sell the beater. Odds are you can get about the same amount of money as you paid. Previous riding experience also means you could probably handle the C50s from the start, just take it easy when you get going.