I agree, Fireworks rocks for me.

We've had these discussions many times.  let me summarize some key points:

1) We are the ones that have to use the tool to create the designs that make the templates you decide to buy. We get to pick the tools that enables us to create the designs in the best way we can. 

2) People 'mistakenly' think that because photoshop is HUGE and everyone has a stolen copy of it, it must be the de-facto choice of all web designers.  Photoshop and most other pixel editing tools (i.e. gimp, photopaint, corel, etc.) are not the best in class tool for web designers.

3) Exporting to other formats is not like converting a PNG to a GIF.  The layers and frames, and live effects we use do not port pixel to pixel with other formats.  We would spend all our time with folks trying to help them with their new images that don't match to the existing ones.

4) We provide blank logo images with every template so if you don't want to spend the money on fireworks, you can't get your head around it, or you just don't understand it, you can use whatever you want to change your logo. 

5) Alternatives such as Xara do us no good because it's Windows only.  We are an all mac shop. Not to mention, i'm sure Xara is a great app, but I think you'll find it's market share is leagues below that of Fireworks which is part of the Adobe CS3 Web Designer suite.

6) I'm sure Xara, like Photoshop or Fireworks, really only SAVES in it's own native format.  Sure it can import in a limited way a bunch of stuff, just like Phothoshop or Fireworks can, but really there is no PRACTICAL way to create files for every major player in multiple native formats keeping the layers, effects etc.  If you can show me a way to do this where the output is exactly the same for all uses, I'm all ears.  What I've seen with fireworks and photoshop is we basically would need to construct the file from scratch on each software product, and even then there's no guarantee it would be exactly the same between them.  Alas there's not common interchange specification that works well like there is in 3D modeling when it comes to vector/bitmap apps.

7) We picked the best tool for the job, that's Fireworks.  It works native on Windows, Mac, and you can even get it to run on Linux.  It is 500% better than photoshop for doing what we do, with web designs and color variations, and as these professional apps go, it's cheap compared to the likes of Photoshop. Everyone has their own opinion, and of course there going to be those with strong opinions for one tool or another, but we have to pick one.

BTW, iIm not affiliated with Adobe directly, but I am on the Fireworks Advisory Board, so if you have features requests, pass them on to me.  I know file import/export is a big topic with fireworks, but native export to another format with 100% accuracy is really impossible.  The best alternative is import which can be handled better, that's why Fireworks can IMPORT photoshop PSDs pretty darn well, if only Photoshop and Xara would have the forethought to be able to import Fireworks native PNGs we probably would not have any complaints at all.