just purchased my self a Wacom Bamboo Pen & Touch small. it's my first tablet and its awesome! - ill be honest it's a little awkward for me but i think its mainly my posture: So used to staring at my pen and paper while drawing rather than looking into my screen without my hand in sight.
The Bamboo Manga is just a Bamboo Pen and Touch with bundled Manga Studio and Anime Studio. The actual tablet is the same in each case so you're good with either If you don't want the software then go for just the pen and touch, if you want the stuff then go with the Manga. If you really don't want the software but have the money then you can get a Pen and Touch and a wireless module with it.
As for the pen nibs. The surface of the tablet is rough like paper. This gives you a more natural feel than drawing on glass. The pen nibs wear down after a while and they'll either get sharp or just stop working as well. Then you have to replace the nibs. How often that will be for you depends on how much pressure you use when drawing and how much you use the tablet.