I figured that. Thanks mkrishnan. When in doubt, there's always a program.
I personally use SafariStand because it's free -- it does scads of other things, so you may end up wanting to go through and turn a lot of them off. You'll have to make two changes -- first, the one in the plugin to force links that open in new windows into tabs (Stand menu -> SafariStand Setting -> General -> Open '_blank' in New Tab) and second, the one in Safari to do the same for links from apps (Preferences -> General -> Open links from applications... in a new tab....).
I do think I end up needing plugins to make Safari a happy experience. This is what I use:
Taboo - warning if you try to close a window with multiple tabs open
SafariBlock - Basic adblocker like AdBlock in Firefox
SafariStand - Does a variety of things, but I just use it for the above
Inquisitor - search-as-you-type Google results.
The first three, for me, admittedly, do things that essentially make Safari act more like Firefox. The last one is more unique.