Hi TK! Silver Wings are fantastic if you're into low 'n slow GA. But just try them ... there are so many packages available ...
I'll not go into the payware side of thins so I'll stick to freeware

For great skies I'd go for FS SkyWorld, you should be able to get it here on SimV. Of course you'd need all off Nick's enhancements like lights and smoke effects and the Airport Environment Upgrade. Both are available here.
I made sort of a check list for my FS9 installation; I mess up so much that I end up formatting my system every half year
I always use this list to remember what was on and what not ...
The [X] means I have it installed right now ...
[X] Flight Simulator 2004 Base Instalation
[X] Flight Simulator 9.1 Update
[X] Flight Simulator 9.1 No CD Patch by Vengeance
[X] Default XML Replacement by Eddie Batista ( //
batista777@hotmail.com)
[ ] FS9 Configurator version 1.4 build 9 by Ken Salter (saltydogfly2.avsim.net //
ksalter@avsim.com //
kensalter@msn.com)
[X] FSAutoStart version 1.1.9 by Ken Salter (saltydogfly2.avsim.net //
ksalter@avsim.com //
kensalter@msn.com[X] FlusiFix by Wolfgang Picheta (
www.flusifix.de //
wolfgang-picheta@online.de)
[ ] FS9.CFG Tutorial by John van Kampen ( //
yahia786@elite.com)
[X] SnapShooter 2.11 by Johan Johanson (
www.nomadsoft.tk //
johan85@hotmail.com)
[X] Aircraft Viewer Background Replacements by Frederic Nadot (perso.club-internet.fr/fnadot //
fnadot@club-internet.fr)
[X] View Module by Flight1 (
www.flight1.com)
[X] Recorder module 1.2 by Matthias Neusinger (
www.neusinger.net/recorder //
recorder@neusinger.net)
[X] Fly By 2.0 by Valery Stenin (
www.geocities.com/vstsim //
vstsim@yahoo.com)
[X] FS SmartVIEW by fsutil (fssmartview.fsutil.com //
fssmartview@fsutil.com)
[X] FSUIPC 3.48 by Pete Dowson (
www.schiratti.com/dowson //
[X] Ultimate Terrain Europe by Flight1 Software (
www.flight1.com/products.asp?product=uteurope)
[ ] Ultimate Traffic by Flight1 Software (
www.flight1.com/products.asp?product=FLT-UT-001)
[X] Flight Environment (+1.30 update) by Flight1 Software (
www.flight1.com/products.asp?product=fe2004)
[X] Ground Environment 2006 (+1.06 update) by Flight1 Software (
www.flight1.com/products.asp?product=ge2006)
[X] ActiveSky 6.0 (+Sercie Update 3) by HiFi Simulation Software (sales.hifisim.com/asv6 //
support@hifisim.com)
[X] ActiveSky Weather Adventures Vol. 2 by Scott Gridley (
[X] Project BlueSphere by Gerrit Kranenbarg (members.chello.nl/g.kranenbarg/gwkhome/BlueSphere.htm //
nisqatsi@chello.nl)
[X] FS Water by Flight1 Software (
www.flight1.com/products.asp?product=esdfsh2o)
[ ] NL2000 scenery 2.92 (
www.nl-2000.com)
[ ] Lensflare Effect Replacement by Eitan Daniel ( //
eitandaniel@hotmail.com)
[X] Nick's LightFix by Nick Needham ( //
klondikekit@yahoo.com)
[X] Nick's Touchdown and Vortex FX (
[X] Nick's Prop Dust v2.0 with Nick's ALL WET (
[X] Nick's Massive Crash Final
[ ] Dynamic Water Textures v16 by Peter Wilding ( //
p.wilding@btopenworld.com)
[ ] TreeGen 1.0 by Feng Zhu (
www.fengzhudesign.com/fs //
fenzhu@yahoo.com)
[ ] Tree Replacement Textures by Mick Posch (
www.mickposch.com //
mick@mickposch.com)
[X] Alternative Autogen Textures by Valentin Casares ( //
valen067@hotmail.com)
[ ] Sunmod 2.0 (Sun textures only) by Vince van Veen ( //
vince.van.veen@hccnet.nl)
[X] UK2000 Scenery (parts 1 to 8 + London Airports, Gatwic Pro & Heathrow Pro 2.00)
[ ] Gatwick 2004 by Online Simulation Solutions
[X] VFR Terrain England & Wales by Horizon Simulation
[X] VFR Terrain Netherlands by Horizon Simulation
[X] Alternative Building Textures by Anselm J