Do you mean "not" the exchange server?
If so, I've been using gsyncit and love it. Tried CompanionLink first but it didn't sync the catogories (placed them in notes) and put weird dashes in my contacts names (only when browsing contacts on phone, doesn't show after clicking on them. Very weird).
Took me almost a year to jump out and try a service... finally decided to give someone a chance after I FINALLY had the thought that I could do a one-way sync like I used to with my blackberry.
I still one-way sync, but it's so much nicer than having to update contact info in two places.
Something to think about - most of the syncing programs out there sync with Google and then Google syncs with your droid. I love it this way since I don't have to ever plug my phone into my PC, but some have an issue with Google managing all their data.