Is there a way to link calendar, mail and address book

I am trying to move away from Outlook. So many problems. But I resist and put up with it because Office is so integrated. I can book an appt, send it to people and send email directly from Contacts. I can do everything from one application. Apple hasn't tackled this. Is there something out there that links all 3 and also has a calendar compatible with Outlook -which is what all my clients use? Otherwise I'm back to MS. Arhghgh. This is the one area where Apple is very weak.