My favorites:
Samdim Tu-114, hands down funnest yet most realistic Cold War era airliner for FS9 (anything Samdim is good)
HJG 707s, also extroardinarily fun and realistic despite the lack of a VC
Hovercontrol Bell 412, best heliciopter built for FS9
Glacier Bay scenery found here:
http://www.simviation.com/fs2004scenery102.htm funnest and most realistic scenery I have found yet.
Golden Hawaii scenery and planes by Bill and Lynn Lyons. Also very fun.
Grumman Goose package found here:
http://www.simviation.com/fs2004props80.htm definitely one of the best modeled plane and effects I have found yet, also some cool flights.
Stearman Kaydet and Eagle Field package
Stearman Model 75 Duster and Sprayer, found here:
http://www.simviation.com/fs2004vintage49.htm Best modeled aircraft I have ever seen, though it runs quite slow due to the high detail. The engine will even predetonate if run at full throttle for over 5 minutes.
Area 51 pack found here
http://www.simviation.com/fs2004scenery93.htm The most accurate and complete scenery for the site and the related airports that I have seen.
Lionheart creations aircraft are also very fun, although not usually realistic at all. I must admit that I like the Dauntless concept though, very sleek.
Also, any if the kneeboard web browser add-ons are great, as well as a few of the music ones (I still prefer just using iTunes though).
Also Also, The new Cessna 150 (Can't find the link again, pretty sure its not here) is absolutely awesome, and doesn't kill the framerates. It has some old school navigation features that I believe should be compiled into a package for any plane.
The F-5s and F-20 packs located here:
http://www.simviation.com/fs2004military72.htm Collect them all! Though they have a lack of range, navigation, and/or autopilot, they are by far the funnest jets I have flown (other than hovering an F-14, but that would count as a rocket, not a jet, right?)
Anyways, that's just a sampling of my favorite aircraft and sceneries for FS9 (I have over 300 aircraft, all of which are at least pretty good), a full list would be too long to read, let alone to spend the time writing on an old thread that will probably die again within the week. Anyways, I'm sure some of these are already on here, but they deserve reiterating anyways.
-Spades
low and....well....just low.