Murahachibu,
I am not entirely sure how many there are in addition to the ones in Logic Express but I am pretty sure that the additions are due to the Jam Packs. Logic Pro comes with all of the Garageband jam packs. More specifically the Rhythm Section Jam Pack ( http://store.apple.com/1-800-MY-APPLE/WebObjects/AppleStore?productLearnMore=MA3 75Z/A), which you could buy for $99.99 instead of buying the whole pro version. As a suggestion if you are looking for that 'real' drum sound from a software instrument I would suggest buying EZDrummer ( http://www.toontrack.com/ezdrummer.asp). It is a great plugin and has that real drum sound. Plus it has drum kit packs that you can buy as well. Its a great product.
-Tyler
I am not entirely sure how many there are in addition to the ones in Logic Express but I am pretty sure that the additions are due to the Jam Packs. Logic Pro comes with all of the Garageband jam packs. More specifically the Rhythm Section Jam Pack ( http://store.apple.com/1-800-MY-APPLE/WebObjects/AppleStore?productLearnMore=MA3 75Z/A), which you could buy for $99.99 instead of buying the whole pro version. As a suggestion if you are looking for that 'real' drum sound from a software instrument I would suggest buying EZDrummer ( http://www.toontrack.com/ezdrummer.asp). It is a great plugin and has that real drum sound. Plus it has drum kit packs that you can buy as well. Its a great product.
-Tyler