Actually, one of my hopes for Aperture 3 was that they would open up the RAW processing pipeline to third parties, so that Canon, Panasonic, et. al. could incorporate their own algorithms into the app. A pipe dream to be sure, especially for a company like Apple, but I think it would offer a much better plugin architecture than either Apple or Adobe are offering now. Forcing plug-in developers to take over image processing after the RAW is rendered to pixels strikes me as utterly pointless. It's far better to use the Photoshop versions of those plugins with smart filters.
Thats not how it works. ALL the camera mfg's keep the raw processing engine a closely guarded secret. You would probably have better luck breaking into the coca-cola factory and stealing the recipe for coke.
Contrary to belief, the camera mfg's do not work in ANY way with app developers on the raw engines. I recently read in this months photoshop user magazine that the single thing the photoshop team was most proud of in the latest version of Photoshop (cs4) was the raw engine they created. That tells you how much work and effort they put into making your raw file look as good as it can be.
I was actually suprised recently when I compared DPP's output to the new lightroom 3 beta. (which uses ACR I believe). For the first time ever, it actually looked like lightroom looked BETTER than canon's DPP. In the past, Nikon's Capture NX2 and Canon's DPP ALWAYS looked better than any 3rd party raw processor. Im not sure I can say that LR3 beats Canon's DPP all the time, but for the brief comparison I did, it sure seemed like it. That to me is amazing. The one thing that I hated about Aperture 2 was the raw processing on the Canon 5d2 and the 7d. It looked like my cat took a dump on my pictures when I was viewing them inside Aperture. Hence, my old workflow was using DPP, to tiff, import to aperture. Which defeats the whole purpose of raw and non destructive editing inside aperture...so Aperture 3 Is a huge welcome to me.
Please explain by what you mean that "plugin takes over after the raw is rendered to pixels". I don't understand your statement.
I can't even install the darn trial on my computer. Keeps hanging after I click install. Sheesh!
Try booting off the snow leaopard dvd, go to disk utilities, scan your hard drive for errors & permissions.
Try it again..if it still doesen't work, uninstall your old version of aperture. To do this, do the following: (note, your plugins for aperture will be deleted, as well as the aperture app, the only thing left will be your aperture library under your home folder, which by default is under the pictures folder (or wherever you have your aperture library located)
To delete previous versions, start Finder, go to applications, drag the aperture icon to the trash. then back in finder, go to your hard drive (under devices), click Library, then click Application support, go to Aperture, delete that folder.
MAN! I havnt been this excited since I was 12 and the nintendo 64 came out!
LOL, you must have been born around '68 too then huh? 
I remember having a Atari 800, with the basic cartridge and the cassette tape recorder to save it!!
what was worse was when they had atari magazine, and would put the binary code for a game in each issue. You would type for HOURS 0101010101010110101010100 and then it wouldnt run. So you would run the check, and then it would say everything was ok.
Then you would wait until the next months issue and sure enough, they would say there was a misprint on the previous issue and give you the code and the line number to fix it. lol, wow, goes to show you how desperate we were back in those days.
Haha, that would take me a week or more to download that

Wow, where are you located that you have speeds that slow? even the cheap $15 a month DSL gives you about 300kb/sec, which still isnt very long to download 500Mb. I feel for you. Slow internet sucks.
Im guessing your on a dialup in a remote area??
on another note.........
Another thing that people dont realize is that to really take advantage of Snow leopards 64bit kernel, you need to boot Snow leopard into 64bit. That way your OS is running in 64bit as well as your apps.
This is assuming your computer can boot into 64 bit mode...to check to see if it can...
====================================================================================================
========================
To determine if your Mac has 32-bit or 64-bit firmware, copy/paste the following command shown in red into Terminal (Terminal is found in the /Applications/Utilities folder):
ioreg -l -p IODeviceTree | grep firmware-abi
====================================================================================================
========================
If it comes back and says "<"EFI64">, you can boot into 64 bit mode.
If it says <"EFI32"> then either you need to update your boot EFI firmware or your computer isnt capable.
To boot into 64 bit mode, hold the 6 and the 4 key down while your computer is starting up.
Then click "about this mac", then click "more info", then click the software tab. It will say under "64-bit Kernel and Extensions:" either YES (if you were successful in booting 64 bit mode) or NO, if you are still in 32 bit mode.
If you want to ALWAYS boot into 64 bit mode, use a app like text wrangler (free) and do this:
Edit the file:
/Library/Preferences/SystemConfiguration/com.apple.Boot.plist
Insert arch=x86_64 into the Kernel Flags field. <---- this is the only thing you need to do. everything else stays the same!!!! Look below, see where it says <string>arch=x86_64</string>? By default, it will not show arch=x86_64!
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple Computer//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
<key>Kernel</key>
<string>mach_kernel</string>
<key>Kernel Flags</key>
<string>arch=x86_64</string>
</dict>
</plist>
Lastly, I spoke with both Onone software and NIK software and both are releasing the 64bit plugins for Aperture 3 in the near future (sometime in 2010)
-Geoff