Our desktop phones are cheap (AT&T 957's) but our phone system is full VPN VoIP w/software for full control through each user's PC and is integrated with our database software. It's pretty cool. All phone options (including voice mail/call forwarding) are handled in Windows and I can call out to each contact with a single mouse click or, on incoming calls, it caller-ID's the incoming number and if that number is found in the database, it pops up the contact right away.
edit: I also have toll-free with extension, direct-dial (local number), remote voice mail administration, call-forwarding/call-routing with a ton of varying rule sets (time of day/day of week/etc.) and direct-dial fax (handled by fax server and served up to my desktop via email). But then almost my whole business is over the phone and I have to be available to my customers/contacts 24/7.