You might like Glims. It's free and offers numbers search engine choices as well as tab management, full screen mode and can be easily accessed from Safari / Preferences.
Compatible with v10.6.5 and Safari 5.
Note: "Using both Glims and Saft on the same browser could have unexpected results"
I use Opera since I don't like Safari book marks and because YOU CAN'T ADD YOUR OWN SEARCH SITE.
On top of that, it seems like when you do web search from Spotlight it uses Safari's search site default, not Opera's.
Funny thing about that whole OS/Web intergration. One company got sued for that. Is Apple going down that road?
And WHY can't I change it! This is beyond even stupid on Apples part. Give me 3 of the multi tracking search sites and not something like ixquick.com.
I'm on the same rant as you with Apple on a whole slew of things. And the only answer I keep coming up with is: GREED.
This is not the same company I knew even ten years ago. And it's why I'm slowly but surely moving to Linux. I looking at my Ubuntu box out of the corner of my eye as I write this.
About search with Safari- you're absolutely right. DuckDuckGo has gotten some attention lately and I was surprised to find my website coming in as number two on its results. Now I will say, i did come in on the second page of Google as well, which is pretty awesome, or at least I thought. Maybe I'm being tricked, ha ha.
But there is no way I can add DDGo, to that list. I use yahoo.co.jp search all the time, and I can't add that either. What it boils down to is where you live and where you're likely to spend your money. This is not about integration, it's about consumerism and big bucks in the digital age. And we're the pawns. I'd say good on ya with Opera. I still use Safari mostly because it's pretty, and I have to admit I need to try Opera more. I use Firefox as my backup. The only solution given here is even worse carp: Glims! Shoot me now....
I'm waiting for someone just to grab a spaghetti bunch of algorithms and release as a generic 'My Search Engine 1.0' that you rename and customize yourself. It's coming. And those of us who are not drones will be wanting it.