Safari 4.0.3: "un-update" or locate "turn features off" buttons?

Question

Pardon me if I'm a bit confused; this is the first forum I've visited that seems to prefer new threads to posting in related threads. I think.
Short version: I got the "updates available" message a couple weeks ago, and I updated. I now have Safari 4.0.3 and I hate it. I mean I really hate it. This is really disappointing for me, as Safari was the first ever pack-in browser that I really loved.
I have many issues with it, one of which (with the help of a thread here I stumbled across) I have semi-resolved, but am still not completely happy.
So I would like to know if anyone can tell me one of two things:
How to "undo" an update and go from something I loathe as much as Explorer and back to something I adored.
Or
How to "turn off" the following irritants:
the "Top Sites" feature. This is just irritating. I use my computer at home for research. When I have pulled the information I need, I will only rarely ever need to revisit a paper. Though it's nice to know (for example, when researching STDs, that I always had on tap a large number of pictures of dripping groins, available even when the kids are playing games on Nickelodeon (ask me how I know this). Further, my computer at work is a shared computer, used by myself and four salesmen. This feature has resulted essentially in the salesmen all giving away to each other their "secret sources" for various materials. Since they're all on commission, this has resulted in a great deal of conflict there. Gotta love that.
Yes; I am well aware that I can "clear history" when I'm done with the net. The problem is that I don't want to clear the history from my home computer; it's something the kids can't just stumble across, and it is handy while I'm writing a paper, since it contains every site I've visited since the last clear.
The "page through" view for Bookmarks. Since there are no pictures that go with most of my Bookmarks when I'm writing research papers, I find myself scrolling through an endless procession of little black record albums, all with the Safari compass logo. Boy Howdy, now that's way better than a screen-filling list I could take in at a glance, yeah, Man....
I don't know what it's called, but that irritating "second layer" that spends sixty seconds or so generating a preview of something every time I mouse over an attachment thumbnail. 1: I don't always want to look at it. 2: it's faster to simply click it and open it in a new window or tab than it is to wait on this feature 3: opening it in a new tab doesn't completely stop me from browsing the rest of the page.
Actually, at this very moment, the "updates available" icon is bouncing on my dock, and I'm not going to click it until I see some reports of what the update is and what it does and how adversely it has affected folks.

Answer 1

Thanks for the reply, Golden Shoes.
I can't say that 4 is faster than what I had. I had a major speed issue with it, but I found advice about changing the numbers in the DNS servers blanks, etc, and did that. Sort of. I've only got room to enter one number; no way to enter both. But it did help, and the loading speed is almost up to what it was pre-update. While it's still a bit slower, I can live with it where it is now.
As for the Cover Flow advice:
Will that remove cover flow as an option completely? It's not that I don't like Cover Flow; I love it for perusing graphic files, etc. However, for running through my Bookmarks, it's horribly inappropriate.
I really don't want to use the Top Sites feature, however. I strongly dislike it, and am surprised to see that there is no option short of recoding to turn it off. I don't wish to sound like someone trying to make a sarcastic point with this next question, because I am being very serious:
Have a made a big mistake buying a Mac? I do not know how to read, write, or edit code, nor do I feel particularly comfortable that I could learn to do such a thing. Is there commonly a need to work directly with the code when "tuning" a Mac?
Just so you will have some background:
At work, we went to aluminum iMacs because the entire company was so disgusted with Vista that even the Board agreed we'd come out with less expense and lost hours swapping systems entirely as opposed to coping with Vista. I liked the iMac I was using at work so much that I bought one to replace my XP box.
But I am not by any stretch of the imagination more than just a "user." If changing code is the norm (as opposed to Preference or Finder toggles), I may have made a very expensive mistake.
Sorry for the digression; frustration coming out, I suppose. Ha!
If it's not too much trouble, can you clarify the results of pasting in the command you suggested? Will it completely disable the Cover Flow feature, or will it simply turn it off in relation to Bookmarks?
Will it completely disable the Top Sites feature?
And-- embarrassingly enough-- what is Terminal? Where do I find it?
Looking at the updates doesn't help. I "looked" at the last one. It said "Safari 4.0.3." There was nothing there to indicate "makes this and this mandatory and slows browser to a crawl."
This update similarly gives a name and series number, but nothing that would indicate if it's something I do or don't want (like Safari 4.0.3: it seemed like something good, but it's a long list of non-undoable "do not want" 'features.' ).
Is there anything that can be done about the mousing over a thumbnail automatically knocks you out of browsing to open up a representation of the file contents?
Thanks for the time and the advice. I apologize for knowing ... well, absolutely nothing.