Notices

can someone recommend the best PDF reader available for the N900? Have a load of books in pdf format that I'd like to read while travelling etc.

The built-in PDF reader does a good job. What specific feature are you looking for?

In devel so Warning apply:
http://maemo.org/packages/view/evince/
http://maemo.org/packages/view/epdfview/

@Manavas
Probably at least some of these
Bugzilla pdf-reder enchantments

There unfortunately aren't many choices yet. The stock browser works, but it's very minimal, and slow. Evince is half-ported, and available from -devel (standard caveats apply), but while it has much better performance than the stock reader, and some other nice features, it still kills kittens from time to time, so I wouldn't recommend you use it unless you have to (I use it for reading digital textbooks so I can leave the heavy dead-tree ones in my room, and for that sort of thing, the performance is needed). If you do use Evince, note that Ctrl+Enter toggles Fullscreen - being only half-ported, it doesn't yet have the nice hidden thumb-button to get you out of fullscreen mode.
If there are any others available, I haven't tried them. Depending on what your content is like, you could always run them through a PDF->HTML converter (such as the command-line pdf2html app on Linux (I have no idea what else is out there, but probably lots)) for the mean time.
I seem to recall there being at least one other PDF reader available for Maemo 4/N8x0, so you could always try to convince someone to port it for you, or finish up the Evince port. Offering tangible forms of "encouragement" (read: bounty) is always an option, if it's worth it to you.
Sorry that I couldn't be of more help.

Aha! Yes, ePDFView was the other one I was thinking of. I haven't tried it.

Enchantments? You mean we need magic to make the PDF reader work? ...Figures.
*ducks and apologizes*

Well I personally am missing the ability to open more then one pdf at a time, that the viewer doesn't remember where I was when I open a file, and (dear god how was this missing) no search!!
I have tried epdf but it was not really ported to a touch friendly interface, is evince any better?

Yes. Sometimes when i read bugzilla or brainstorm I think that lvl 14 mage could do some magic to stuff. :P

.edit
And yes it´s typo

Ok, it's able to open pdf files, but:
1) It's not easy to move inside a 1000 pages document.
2) It's not possible to make "search" of words.

evince is wonderful and has kinetic scrolling. What was it that you consider it so badly ported? I usually read heavy stuff in it and I have no complaints.

Evince's GUI is still very messy on Maemo, and not particularly finger-friendly. The scrolling kinetics are a bit off, too. That said, it's quite fast, and reasonably featureful. As I stated in my previous post, you probably shouldn't use it currently unless you need its features, and don't mind dealing with its flaws. Evince on the desktop was pretty good last time I tried (which was quite a while ago), and it would be nice to see the Maemo port get some love.