Hi again, a lot of different things go into choosing the right bike. Sportsters, are more like the hot rods of the harleys. They get a bad rap from the all the guys that have the bigger bikes. Then you have the Buells they are the sport bikes that they sell. Then you got the big v-twins, thats the ones that everyone wants. FYI - Harley has a program that if you buy a sportster they will buy it back a year later and give you your money back if you buy a bigger bike. This could be a good place to start if that program is still available.
I have been to the dealer when they had a open house where you could ride any of the models. This is very helpful when choosing a bike. Maybe they have one coming soon in your area. Never the less if I were in your shoes I would ride as many different models that you can so that you find the bike that you really like and fits your riding style. If you go for a big v-twin get one that is at the least an '09 they did a lot of upgrades to them that are very important one being the frame. Have the dealer give you a test ride, they will do this, if they say no go to another dealer.
Used bike in this economy could be a good deal too.
I hope that you take you time in choosing the right bike and you enjoy the sport as much as I have and most important ride safe and take the safety class that was recommended in the other thread.
Good Luck and I look forward to seeing you on the road!
Glider