What should my first motorcycle be?

Hey guys,

I'll be looking at buying my first motorcycle this weekend, and I've been doing tons of research on the best bike for me, but I'm a bit torn.

I took the MSF course on a 125cc cruiser and really liked the cruiser riding position, so I am leaning towards a cruiser - they have a low center of gravity, a linear power band, and forward controls, which I like.

But the problem is, cruisers are heavy and expensive, and the one's that aren't are under-powered. I'll be looking to finance my first bike and pay it off within a few months (it's my personal decision - please don't just say 'buy used'), and can comfortably spend up to about $7000. I could spend more than that, but I'd need to keep the bike for a long time to justify that.

I really like bikes like the honda rebel or vstar 250, but they can't handle the freeway, which is a concern for me - in my area, people go very fast on the road. But the next step up - the 750s, seem like really heavy/big bikes for a beginner.

With those needs in mind, do you guys have any suggestions on what my first bike should be?

Thanks!
Added (1). Additional info:

I've ridden my grandpa's Moto Guzzi 750cc Standard, and could handle it okay - (it's 450 lbs)
Added (2). Also, it helps to know that one of the reasons I'm getting this bike is to go on rides with my grandpa, so being able to ride for longer distances comfortably is preferable.

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