Pinnacle Impression DVD Pro v2.2 works a treat (Its what I use) and I have heard good reports from colleagues using Sonic ReelDVD v3.
NB, the lesser versions of Sonic's products can prove troublesome esp on VIA chipsets with AMD cpu's.
Hope this is of some help.
Depends on what you want to do, scenarist as explained sits at the top of the tree as far as features and compatability is concerned (features Dolby Digital etc. which lower systems don't have because of licensing expense.) But its like £15,000 + plus system. I'm not sure but I think you have to buy it as a complete systems.
ReelDVD is its little brother and features a lot os the big S's stuff, but I find it clanky. But it produces good discs.
Impressions PRO and the lightweight SE, are both dead easy to use, (akin to working with premiere) but are extremely unstable, but are getting better. Once you've got your head around the bugs you will be okay. Menu systems have to be designed in photoshop though. Impressions will burn and image straight from the timeline which saves you going to external programme.
There are cheaper programmes such as DVDworkshop and dazzle, but they're really restricted in there handling of files.