I use Openoffice and Thunderbird, but one drawback is that most cellphones can synch contacts and calendar with Outlook, but nothing else. This means that
A) I have to install Outlook so I can backup my data
B) I have to launch Outlook to access or edit it.
This is a pain and I wish I could use Tbird for everything, but alas......
The only problem i had with Thunderbird+Sunbird+Lightning is in fact the CALENDAR stuff (and the part that it's a kind of disjointed solution vs. Outlook which is "all-in-one"), it's not as polished as Outlook and i had alot of issues if i set up a meeting with people who are not on Thunderbird themselves [the meeting request is not the same as Outlooks and vice versa...need to fiddle with settings and whatnot]
Online syncing (aka "syncing into the cloud") imho is the way to go these days. Basically you sync to an online service, Gmail being one [there are others like
http://scheduleworld.com/sw2/index.html which are pretty good too] , and then let all your devices/clients sync with Gmail [online service]. You don't actually need to use the online service directly if you prefer using your flavor of desktop software [i.e. outlook], but you no longer need to worry whether your desktop/phone can sync between each other as the online service provides the tools to sync to it instead.
So in short:
1. sync calendar+contacts between Thunderbird+Sunbird <--> Gmail
2. sync calendar+contacts between Gmail <---> Phone
Here's some tips/tricks/guides on how to do this :
http://lifehacker.com/399407/how-to-sync-any-desktop-calendar-with-google-calendar
There's ALOT of free/open source tools to do above, depending on your devices/OS/Desktop software etc etc.
I've found with this config i'm not tied to a specific OS/Software Package anymore, worst case i have it all right there in my browser.
I currently do it anyway with Outlook <---> Gmail [with Google Sync] and then Gmail <---> Windows Mobile Device using ActiveSync.
Oh and finally, i set up Gmail to "pull" my mails from various accounts as well [you can set up to 5 accounts from which gmail can fetch mail] . So you can set up Gmail to retrieve your Work/Whatever Email every hour...this automatically serves as backup right there.
So this implies i can access all my contacts+calendar+email in my browser from any PC , whether i have outlook or not AND sync it to my phone+desktop if i do not want to live in the browser.
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