Logic's EXS24 sampler instruments are an excellent starting point.
Kontakt 4 contains a boat load of sampled acoustic instruments.
Battery 3 " " " " " " drum sounds.
The above can be obtained individually or as part of Native Instruments Komplete 6 which also has a wide range of synth instruments.
Kontakt 4 may be all you need.
I just recently added the Kirk Hunter Ruby orchestral library. Many articulations to choose from among the excellent sounding instruments.
You didn't mention audio processor plug-ins. For native solutions I like all things PSP, and the newer Nomad Factory EQs & dynamics processors.
UAD is an an outstanding DSP solution.
I'm a frantic user of the SoundToys Native Bundle. Have always liked some of the typical Eventide style spicing. I also love minimal club mix style sound design that rely on "playable" as well as tempo synced filtering. The SoundToys plug-ins bring home both these apart sound worlds to my studio and live rig.
I have the same type of question as the original poster. I just jumped in both feet to Logic Express and have been surfing around to see what's out there. I've picked up a few of the free samples out there and listened to the demos. It's hard to decide since there are so many. Maybe just stick with the "out of the box" sounds until I get more proficient...
My music style is varied - straight rock, punk, ethereal to new agey (depends what instrument I start with and where inspiration takes me).
The options are overwhelming these days, and many of such high quality. For orchestral, I still like the old Vitous libraries for the warmth, realism, and natural recordings. The VSL libraries are recommended by many for the playability and programming of articulations, with a completely dry (some might say "sterile") recording style in contrast to the hall recordings of the Vitous.
For piano, the Quantum Leap pianos are superb, as is Ivory (I prefer the sound of the former, but you should listen to the comparative demos online and choose according to taste and style of music). It's also worth checking out PianoTeq.
For other sounds, I would recommend anything on the Play libraries by EastWest (soundsonline.com), as well as the Spectrasonics libraries (Omnisphere, Trillian, etc).
If you are looking for excellent keyboard (organ) sounds, check out Scarbee's products, which are soon to be distributed via Native Instruments exclusively. NI already took on his top-notch electric bass libraries (highest recommendation for those).
Kontakt is certainly an excellent starting point. Kontakt has become the de facto standard format for sample libraries now, and with good reason. It's a very deep programmable (scriptable) engine, with excellent sound quality. The included library is very impressive, and is probably the best single starting point if you are interested in expanding your sounds.
Flux's BitterSweet - Powerful and flexible transient designer
Brainworx's bx_cleansweep - One of the very best sounding low and hi cut filters EVER
Airwindows' Channel - Nice console drive emulation
Sam's Chip32 - Cute little blippy synth with flexible waveform
TAL - almost everything they make is fantastic: fx & synths! all free
Chipsounds' daHornet - nice classic synth
dfx's MIDI Gator - side chain gate with attack release and volume
Luxonix's LFX-1310 - multi fx rack
Betabugs' Monsta Chorus
Green Oak's Crystal - synth
TT Dynamic Range Meter - shows average dynamic range of your track
GSi's WatKat - Fantastic retro tape delay (use with a gate or it goes on forever)
Great idea to post favorite freeware! That should be an ongoing thread here. The quality of audio freeware (and shareware, and inexpensive small company products) these days is often so high that it rivals or exceeds the plugins from the major manufacturers.
It's just that there is such an overwhelming flow of freeware, that it's difficult to find the gems. So recommendations are very helpful...
AirWindows Desk - used on every track, it's gives a better sum in most cases
AirWindows Cojones - if you thought your drums sounded good before, apply this
AirWindows LeadVox - i dunno, just magical. butter and jam on my vox toast
AudioEase Speakerphone - i want it to sound like it was put in a safe, dropped underwater, recovered, blown up and mic'd with the seaweed still attached. done!
BBE Sound D82 Sonic Maximizer - fast audio fix, i hear the H82 is terrific too
Brainworks BX Control - M/S routing and absolute best sounding mono filter for low end
Camel Audio CamelSpace - step sequence FX heaven
Melodyne Editor - Direct Note Access is nothing shy of fn voodoo, when used by someone who knows what they are doing. it is SHOCKING. I've perfectly separated and moved notes of completely distorted guitar. my test blow away the examples on the site. i can't wait until it makes it into Melodyne Studio
D16 Group - I like all their FX boxes, fat analog sound
IK Multimedia Single FX plugins - I like most of them. Try them and buy what you like
iZotope - I like everything they do
Line 6 Podfarm Platinum - Great for waaaay more than guitars
LiquidSonics Rerverberate - Far and a way the best convolution reverb out. fast and furious
Mathew Lane DrMS - best mono to stereo and stereo field manipulation
PSP - I'm a huge fan of nearly everything, but the sQuad EQs and PSP-84 are NOT to be missed
Sonalksis TBK - overpriced, but the only resonate filter i've ever heard that sounds like a clean pass-through when the filter is all the way open--valuable in house music transitions
Sonnox Oxford Inflator - Boosts richness and perceived gain without compressing at all
Tone2 Warmverb - Best jack-of-all-trades on the planet. BIIIIIIG sound. ideal for vox and synths
U-he Uhbik pack - Fantastic bundle. lots of applications
Universal Audio UAD - a few plugs i can't live without are: fatso sr, pultec pro, Neve 1073, the list goes on
Synplant looks really cool and original, plus the sounds are amazing in the demos.
I have been looking at the Stylus RMX demos and am attracted to the ability for the patterns to "freeform" like a real drummer would. Can some of the other drum plugins do the same kind of randomization?
Alchemy looks way complicated, but the preset demos are incredible. I would probably not want to dive too deep into such a complicated engine??
Sampletron - Wow! I love the sounds I hear. Showing my age maybe...
The IK Multimedia stuff looks and sounds very versatile. The Total Workstation really appeals to me.
You're very welcome. The developer is a tremendous person as well. Extremely responsive and interested in customer concerns. It is by far the best reverb on the market to me, given the amount of free high-quality IRs available on the net. Cheers!