I recently bought FSX as well, but have been picking the brains of the guys here for the last few weeks or so. Here are some things you may or may not be aware of in FSX
There are many free graphic enhancement programs and there are many 'pay for' graphic enhancement programs. There is freeware addon planes and there are payware addon planes for FSX. The addon planes from some of the companies out there are extremely more in depth then the stock planes that come with FSX + Accelerate. Too many types of planes and software companies to list here. Just let them know what interests you and these guys will be happy to point you in the direction of great planes, be they payware or freeware.
Graphic addons seem to come in a few types. There are the type of programs that concentrate on a particular geographical area and massively increase accuracy and detail and just general beauty of that specific area. Some freeware stuff is here for you in this thread here at NZFF
http://nzff.org/forum/viewforum.php?f=40 Some payware of this type is available here at NZFF
http://nzff.org/forum/viewforum.php?f=12There are also graphic improvements that address the auto generated scenery. This is not area specific and only affect generic graphics that FSX uses. There is some freeware of these and also a very up and coming payware one called VLC (Vector Land Class) which you can read up on here at NZFF
http://nzff.org/forum/viewtopic.php?t=11747 Also on the topic of graphic improving there is a payware program called REX2 which takes weather and water to a new level in FSX.
Hmm, what else, well, tons really. The above is a quick and brief overview of a small part that is FSXing here in NZ

Welcome aboard!
Edit: Oh, very important is how to install FSX. As you likely have only just installed it, it will be relatively painless to uninstall and reinstall if necessary. Details are here
http://www.simforums.com/forums/forum_posts.asp?TID=29041There is a TON of adjustments mentioned there, but the important part is hwo to install. As it outlines there it goes something like this, you need to install just FSX first, then get the game going, and load up the default flight. Then, shut down the program and reboot your PC. Then get out your expansion pack (Acceleration) DVD and then install it. Get the game going again and load up the default flight. Reboot again. It is something like that, but follow the instructions in that link and it will tell you the exact way to go about it.
Edit2: When I started posting here I had some weird default setting for how I viewed threads. The threads were presented in a collapsible format where you had to expand each subsequent post to read it. This can be adjusted in the top right hand corner of any post. You should be able to see it reading this post. You should see an "Options" drop down menu and set "Display Mode" to "Standard"