Bringing up this subject again as rather a late adopter; I've had an N900 for almost a couple of years now but I've never bothered to achieve full synchronisation of personal data. Never really seen the point. Over that time, though, I've become dependent on the N900 for calendaring and contacts, and this brings with it a desire for access to that data in a variety of situations.

I've recently opted for a two-way sync of my N900 calendar against a Google calendar using erminig and mounted that Google calendar on my desktop with Thunderbird + Lightning extension, which works well and leads me to wonder about doing similar things in terms of my contacts, tasks etc.

However, I want to preserve 100% of the data in my N900 contacts - for which Google Contacts is not the answer as it politely ignores the X-FACEBOOK and X-SIP fields in all my N900-generated vCards. So, I'm looking for something against which I can sync my N900 contacts, then manage/merge/edit them from a desktop PC, then expect the N900 to sync any updated contacts back from whatever service. I've never played with SyncML, open to recommendations for third party services and/or to running my own server on a Debian VPS - if someone can confirm that this is the answer.

Anyone got a parallel approach for tasks? If I could add/edit tasks from the desktop and tick them off from the phone, that might make the functionality worth using.

Not so worried about file synchronisation, as there's few files on my desktop to which I need access on the N900, but I wonder about the use of e.g. Google Docs for spreadsheets with mobilised access... is anyone doing this? I'd be interested to hear of any new developments / discoveries in the last year or two; I am now a routine user of Toshl, mail has always been available via IMAP, calendaring now works... if I could add proper cloud-based synchronisation of contacts and tasks I'd be a very happy man indeed. Anyone got all this working?