HTC Desire : Best Sync Method With Outlook And Is Gmail Really A Push Service

I use Microsoft Outlook 2007 as my MAIN email and calendaring software. I will be accessing my mail and calendar via Outlook on my office PC for the vast majority of time.

My main email accounts are currently configured as POP3 but are also configured to leave copies of messages on the server for 30 days, which allows me to check new messages via my ISPs webmail when out of the office.

I have considered changing to IMAP for my main email account but have purposely avoided it up to now as I have a huge number of mail folders and messages my Outlook pst file is currently 7.2GB. A lot of those are for archive reference and I dont need to see them on other devices BUT, as I understand it, IMAP does not let me only select certain folders to mirror and sync between different devices (it must sync all of them) so I feel it would be unwieldy to use IMAP on my account. (If anyone knows of a way to set IMAP to only include specific folders please let me know!).

I do have a Google Mail account already, but rarely use it its just there as a back-up account. I�ve NOT as yet imported my Outlook contacts or calendar into my Google account.

Now I know that I can use HTC Sync to sync up my Contacts and Calendar, but what I�ve read suggests that the phone works best when you sync it with your Google account. I COULD of course import my Outlook Contacts and Calendar into my Google account, and I COULD also use my Gmail account to check mail from my main POP3 accounts. However, Im unsure about going down that route as Im worried that might confuse things, cause conflicts, or cause double-work for me when I update my contacts or calendar from Outlook or from Google. Are there possible problems with going down that route?

Secondly, Im very intrigued to have read that Gmail is more efficient for the phone as Ive read it works as a push email service. That is, I dont need to check my mail by doing a send/receive from my phone either manually or automatically at set intervals, but that Gmail will just automatically PUSH new emails to my phone as soon as they arrive. Is that correct?

If it is correct it sounds good, but does that mean my phone must be or will be permanently connected to the net? As I don�t use my mobile that much Im on a Pay-As You-Go service so need to ensure my phone is ONLY connecting to a data connection when I need it to. Will I be able to work-around this?

I know HTC Sync doesn't transfer Outlook Notes or Tasks. Has anyone found, or can recommend, an app that will do that for me?