I rather read books in english for a couple of years now. And I do think it's often better in this language than it's poorly translated versions in polish. Like, for example 'Alice's Adventures in Wonderland' - I hated it as a child, when I read it in polish, but recently I've got it in english version and its much better. I even started to love it. It's much more deeper, its more eloquent, the metapfhors are well done and it has a lot different meaning for me now. So yes, I prefer to read in english. As I finished my studies of english a few years ago - that's my best way to keep in touch with this language.
I saw many of you resigned of reading in english, because of wrong book.
So, here are my tips for beginners in this kind of reading:
If you really want to start read like that and you're afraid your english is not enought to understand - try with easier one. Not the Harry Potter or Prachett, where more than half of the words are invented by author. Or Memories of a Geisha, where a lot of words are in japanese. Or Shakespeare, who writes all his works in old english. Try something light, like, I dont know, maybe some paranormal series for youngsters like 'The House of Night' by P.C Cast and K. Cast or 'I am number four' by P. Lore.
If you are just about to begin, and you know your english a little bit more - try to find an audiobook version of your book. Try to listen how the words are pronounced. Sometimes, for some people it helps to understand.
And if you really want to read a book in english, and you know that there is a polish version of it, get yourself (from the Internet for example) this polish version, and when you'll read the english one, and you won't know the meanings - you can always check in the polish one.
'Nie mogę teraz o tym myśleć, bo oszaleję. Pomyślę o tym jutro.'
/Scarlett O'Hara z 'Przeminęło z Wiatrem'/