I bought and kept 3 bikes within the first 9 months of riding, so my early bike experience wasn’t all serial, but had some overlap.
I researched a lot on the first bike and got a GS500E (naked 2001 model w/ 7k miles, very clean) on Jan ’09 for $1750. I was a decent mountain biker, but had never been on a motorized bike before, not even a scooter. I’m 6’ even, but the first time I saw a GS500E in person, it appeared bigger than expected and intimidating. The seller rode and parked it in my garage. Couple of weeks later, the night that I completed my MSF class, I took my GS out for the first time. It felt easier to ride and nicer than the Rebel 250 I had in the MSF class. I short shifted it a bit, and still remember the thrill the first time I carefully revved the engine up to 5000 rpm in second gear. That first night I rode about 33 miles, all within a couple of miles of my neighborhood.
I had a few low speed drops on the GS, but it had an engine guard and being naked, took the drops well. Ninja 500 was the other first bike I considered. The Ninja looked sexier, but it cost a few hundred more, and with fairing it probably wouldn’t handle the drops as well.
In June ‘09, I got a YZF600R; in September ’09, I got a SV650N. It was fun to have more power on city streets and freeways, but the GS500E remained easier, less stressful (= more fun) to ride bike on technical roads for that first year. I’m still convinced that the GS500E is the perfect first bike. (A smaller, shorter dual sport might have been even easier to learn on, but it wouldn’t take the freeway as well as the GS500.)