Alright... I have given a lot of opinions over the last few years and I wanted to make a comprehensive thread so I could share them with students who may be interested in going to physics graduate school. I will post some of the data I have accumulated as well as many questions I have answered. I will try to expand on this as much as possible.
Help selecting schools
You can find a roster of physics departments on AIP. There will be approximately 190 in total. This is your decision, not any of ours, so I highly suggest you look through those schools and do the research yourself. http://www.gradschoolshopper.com is also useful. I have spent much time researching each of these schools for my own preferences. I think you should write down your preferences and figure this out as I'm sure most don't have the time to do this for you. If from there you have found some schools and want to ask general opinions about them, I'm sure most people will help you, but nobody wants to do your homework.
-Where would I absolutely detest living? Since you have to live in this place for the next six years or so, make sure it will be a place you enjoy.
-How large do I want the program to be? Many schools out there have massive programs, with nearly 300 students and many schools barely have a program at all (say 0-30 graduate students). Depending on preference, this can take off a lot of options.
-Does the program offer at least a few options that you are interested in? Even though you may be interested in one field of study now, you will quickly find that things can change. When you're looking at schools it is a good idea that the schools have at least a few options just in case your original plan does not go as well as intended.
One thing that is always good to keep in mind is that the final schools you choose should contain a variety. A few schools that you know you can definately get into, some you have a fairly good chance of getting into, but you aren't sure, and a couple of long shots. This seems to be the "safest" bet. =)
Questions about an average GPA
You'll find by looking through most requirements for graduate school that a 3.0 or higher must be attained. Some schools have a 2.75 GPA requirement, and a select few even have 2.5 GPA requirement. I'm not sure how rigidly they base selection on this but if you're above a 3.0, you'll definately have a chance at getting into a school. It may be harder to get into the top-tier schools because of this, but if you can follow through with a wonderful score on the PGRE (such as 95%), and have had at least some research experience, you shouldn't have a problem finding a program that will accept you.
I have an opportunity to volunteer my time at a local high school during the academic year, assisting the teacher and helping students in lab classes and on problem sets. Is this something worth participating in, or will grad schools typically overlook this sort of thing?
Well, let's put it this way. It can't hurt you. If you enjoy helping out with the tutoring or TAing, I would go for it. Otherwise, if you can spend time on other things such as improving your PGRE score or doing research, those would probably be more appealing to graduate schools. I help with TAing and tutoring myself, although the main reason isn't to get into graduate school, it sure looks better than not tutoring/TAing!
Total Enrollment at Schools with a Physics Doctorate Program
One of my main factors in deciding on a school was the enrollment at that University. Since my five years of undergraduate were at a school of approximately 6,000 students, I had grown use to that amount, and it was comfortable. What I decided to do in choosing schools to apply to for this year was to make a list of all of them, in order of their enrollment. I decided to post my work here so others could make use of it if they are as picky as me. =)