This page may hopefully give you an idea what can be done with the templates shipped with Thalassa. Images are clickable.
Smoky is the oldest and the dumbest of the templates shipped with Thalassa.
Its customization capabilities are limited, and it only supports one style
of the comments (namely, the tree style). It doesn't even
provide the possibility to customize the color scheme, at least
out-of-the-box. However, the template still may be useful; actually, this
site, http://thalassa.croco.net, is based on Smoky, using the
cloudy color scheme.
The default color scheme, pretty boring. Click on the image to enlarge.
The twilight color scheme.
The cloudy color scheme. Doesn't it ring a
bell? Yes, just look around, this is exactly what's used for this site.
This template is more flexible: editing its configuration files, you can
choose one of the pre-composed color schemes or invent your very own one,
you can decide where to place the logo image (on the left, on the right, or
nowhere) and the navigation panel (again, left, right or none), and you
can, to some extent, customize sizes and lengths. Besides, this template
is capable of using all the three styles for comments (list,
which means a plain sequence of the comments, tree, in which
replies are displayed right after the parent comment, indented to the
right, and thread, where replies for each of the top-level
comments are displayed on a separate page); you can shoose the style
separately for the guestbook and for the other pages.
The default color scheme, this time even not so boring.
The twilight color scheme.
The cloudy color scheme. To me, for Agenda it doesn't look as
good as for Smoky, but that's a matter of taste.
The allwhite color scheme. Isn't this really boring,
heh? But I created this scheme upon an explicit request.
Remember, this template is initially designed to allow for a custom
color scheme, so you can invent your own one. Perhaps you should,
if you want your site to have some kind of individuality. Besides that, with
this template you can also notably alter the layout, e.g., move the logo to
the right side, and the panel to the left, like it is shown here. Well,
you can move them both to the left, as well as to the right, and you can
hide each of them (although it is hard to go without the panel).
By the way, don't worry about those narrow screens, like the damn mobile phones. Whenever the screen is really narrow, the panel ends up to be displayed atop of the page's text, not alongside with it.
The site intelib.org is made with the Agenda template, using its default color scheme, and the FEDAnet project site may serve as an example what may be done with a custom color scheme.
The Woodpecker template is the latest of the three and perhaps the most
sophisticated: it allows to customize the color scheme (and it is the only
template which lets the bottom of the page have its own color, not the
color of the page head), to alter most of the lenghts and sizes, to move or
hide the logo image, to choose any of the three existing comment styles.
Alas, presently it comes with only one predefined color scheme; it was initially intended to be colored by the user.
I'd recommend to take a look at the rebuildworld.net site, which uses the Woodpecker template with a custom color scheme.
In conclusion, I'd like to remind you that templates are fully optional. Thalassa will happily generate whatever you order it to, it isn't even limited by HTML, any sets of text files may be created. For an example of a site which doesn't use any templates, take a look at the Information Violence site. Not the best "design" perhaps, but at least it is clearly seen it is not based on a template of any kind.