If you are just concerned with aesthetics, you could use QuarkExpress and an XTension "Mathsetter" ($399 from <http://www.bluesky.com>). The MathSetter XTension adds TeX/LaTeX math typesetting capability to some older versions of QuarkExpress (version 4.x or 3.3.x versions equal to or greater than 3.3.2).
If the long-term viability of your files is important, you will need to stay with LaTeX. FrameMaker is clearly not an option in this regard! FrameMaker's only champion at Adobe, John Warnock, is no longer with Adobe---he's the one man responsible for the purchase of FrameMaker. Adobe has already discontinued development of the Mac version and all UNIX versions except Solaris. It seems highly likely that FrameMaker will be discontinued as soon as Adobe can get away with it.
Addons for M$ Word, such as Mathtype (from <http://http://www.adeptscience.co.uk>) or Expressionist (now called MathEQ from <http://www.livemath.com>) aren't the answer either, in my opinion. For one thing, they are specific to Mac and Windows systems so you preclude any future move to a Linux/Unix system. (TeX/LaTeX doesn't suffer from that limitation.) Using these equaton editors with TeX/LaTeX involves some compromises too. For example, when I used Expressionist (about 10 years ago) it could export in TeX format for pasting into TeX/LaTeX files. HOWEVER, Expressionist didn't have a parser for TeX/LaTeX so you couldn't edit your equation again in Expressionist UNLESS the big block of comments Expressionist generated was kept intact. Those comments were Expressionist's notes to itself on how the equation was made. I'm sure MathType uses a similar scheme for TeX export.
I would expect the word-processor-like front-ends for LaTeX (e.g., Lyx <http://www.lehigh.edu/~dlj0/LyX.html> or Scientific Word <http://www.mackichan.com/>) would suffer to some degree from this problem as well. At least for me, there is a distinction between a "LaTeX compatible" file format and a "LaTeX" file.
As for Dave Shaffer's comment regarding TeX/LaTex:
"The main drawback as I see it is that high-priced scientists
have been turned into secretaries."
I would have to strongly disagree. I've known and worked with many talented secretaries over the years and NONE of them could have done what I do with LaTeX. So I don't think that document preparation with TeX/LaTeX can be considered "secretarial work". The bottom line is: if you want it done right with TeX/LaTeX you are going to have to do it yourself.
--Mark