I am also lucky. Now days I feel comfortable enough to speak to my sister, my mum and dad, my doctor and my Psychologist. I also talk to my two best friends about it occassionally, but find that family is more supportive.
It wasn't always like this. I have had DP for more than 9 years and I only started telling people about it in the last year or two. I think it has to do with how understanding and supportive the people in your life are. I mean- the friends I used to have would have thought I was being a sook or would have been scared off if I tried to talk to them. I also didn't know the name of what I was going through (depersonalization) until recent years, so this is probably why I never said anything until recently.
I definately think that telling someone in your life is important. I know as soon as I spoke to the right people about it I felt so much better, and I have no regrets in telling them. But it needs to be someone who will understand and be there for you or you can end up feeling worse. This is why I am so happy we have this forum!! Not everyone has such understanding friends or family or can get access to a psychologist. Just knowing that there is a whole online community of people who will support you whenever you are in need is a beautiful thing.