PRS has 4 main lines of guitars, listed from least to most expensive below:
SE: Korean imports and are the most affordable (generally < $1000 new)
S2: Relatively recently line (last few years) that are made in the USA, but with some cost cutting done to lower their price
Core: The "original" PRS line. These are the "normal" PRS models, for lack of a better term.
Private Stock: $$$$$$
Each line has several models, many of them very similar, just at different price points. I have played many models from all the lines except the S2 and they are all excellent quality. The current models can be found on their website's products page. A history of models can be
found here. They have so many models now that it really doesn't make sense to talk about a "standard" PRS. They currently have a few different neck shapes, many different pickups and body shapes, scale lengths, etc. You've got to narrow down what you want other than just a PRS.
If it were me, I would start with deciding what kind of money I wanted to spend, and whether I wanted new or used. You get a whole lot more for your money buying used and they are great instruments. I currently have 2 CE24s and an NF3 (see my avatar). Both of these models, BTW, are no longer made. Like someone said above, find a place that has a big inventory and try out as many as you can.
Probably the best resource for getting info is on the
PRS Forum. Lots of helpful people there who are every familiar with all models from the 80's until today.