Funny, last night I updated AD2 and clicked on the Register Products tab. I didn't realize what was even there... I found I had 3 kit pieces and a whole extra Kit sitting waiting for my attention. I grabbed the Percussion kit and a a couple of snares. 
Turns out a bonus from first buying Professional and upgrading. You end up with 4 free kits and a bunch of kit pieces. 
This was like going into a music store and someone giving me a new drum set and a few snares! 
Life just keeps getting better. 

Oldish thread, but personally I use BFD3. There's some absolutely incredible snares in there, as well as some amazing expansions. Their Dunnett Titanium kit is damn good, I find myself using it a lot these days.

Sonars Drum replacer ships with Chocolate audio samples. Anyone tried those yet ?
They are great sounding samples. The snare samples for Whole lotta snare sounds like a good Bonham snare.
You have to fine tune them though. I sound stack snare and kick samples.

Man - I forgot about that song!!!  You just made my morning!  Yes - I also was wondering if you meant superior drummer 3 or session drummer.   Superior 3 absoluteley smokes - Not sure about session 3

To be honest guys Ive been looking at the prices of those better packages such as superior or EZ and i really cant afford it.     Heres the game plan.    Keep Session Drummer as a base software but buy some kits or single shots from some of the great links the guys posted earlier in the thread.   I'll then just drag those better sounds into Session D and save them as custom kits.    Well it's a workaround i guess till i can afford one of the other packages. 

I guess your don't have Addictive drums?  
 
The other option as metioned earlier is keep an eye out in the deals forum here and grab Strike 2. I got mine for like $35. It's more complicated than AD2 and SD2 but has a lot of kits for the price you pay. 
 
Adding other samples to SD is pretty easy so give it a go first. 

Cool.   I didnt even know there was a deals forum.......doh.

Yes, if Session Drummer is all you have now, that's not a bad thing. You can take your own samples and bring them in. But you can also use the sounds that come with it by layering your snare sound using your midi snare track. Have one snare hi, another low, another with snap, and still another with what ever you can think of. The sky is the limit! Generous use of compression could help also. Remember, no rules. And let your ears be your guide!
 
 
You say you have X3, but didn't say which version of X3. Even the lowest Studio version has some great fx in there that you can use to help you out.

Yes its just the home studio version.   It does everything I need so I never bothered buying a higher version.  Any extra plug ins i needed i always just bought and downloaded.    All i need really now is just to get better drum sounds and im pretty much sorted. 

I also forgot to mention guys.   I recently bought a Millenium MD-90.    Its one of those electronic drum kits that comes in a single unit.   The plan is to learn drums.    So if I can manage this goal... I wont really need better drumming software per se but just better sounds.     So in that respect maybe just keeping Session D as the basic engine and buying better kits etc would work fine.
I'm looking at the links the guys posted in this thread and single shots are like only 5 bucks and a full kit can be got for around 15.     Those are really good value prices.