...we could be doing a lot more monitoring at many different wavelengths, etc.
A number of the SETI detection methods described in this thread do not require
distant future or hypothetical technologies. They can be done now. This includes
amateur astronomers who have equipment that professionals would have killed for
just 20 years ago.

As just two prime examples for so-called amateurs (and I mean so-called in the
complimentary sense), The SETI League has about 100 people conducting
their own radio searches (http://www.setileague.org/) around
the world.

Stuart A. Kingsley did much to get Optical SETI back on the big boys' map in
the 1990s. This includes detailed information for amateurs to set up their own
Optical SETI observatories. Go to this page and scroll down to the section
titled "Optical SETI Hardware and Software":

http://www.coseti.org/content1.htm

Overall, laser pulses are much more obvious than sifting through millions of
natural celestial radio signals just to find that one potential artificial one.
Of course radio signals have the advantage of being easier and cheaper to
produce and can cover a wide area of space.

A lot of what professional astronomers are doing now could detect the various
types of possible signals and interstellar-scale activities already discussed in
this thread, but for obvious reasons most do not. Or they do it on the side
in their spare time, if we're lucky. Why do you think most SETI folks are
tenured or retired astronomers? Outside of astrobiology, which is finally
gaining a foothold in the academic world, SETI remains marginalized - even
though a large quantity of the public is fascinated with alien life.

It was heartening to see that Fermi group sifting through the old IRAS data
for possible Dyson Shells, even if they did not find anything definite. How
much would it cost to have some grad students go through old astronomy
photos and other relevant data? Clyde Tombaugh found Pluto essentially
by himself with long, hard nights at the telescope and comparing thousands
of image plates with seemingly endless amounts of stars to find that one
little dot that moved. And this was with technology from 1930.

Did you see the report I just posted at the end of this thread on The
Planetary Society's new Optical SETI Telescope? The observing team
(made up of grad students) scanned as much of the sky in three nights
as a similar effort a few years back did in six years!

So, yes, we can do various types of SETI with today's technology and
much of it will not break anyone's budget. Sadly, the effort will not kick
into gear until something definite is actually found, then everyone will
jump on the bandwagon while declaring they knew it all along, just like
with exoplanets.

SETI could use its version of ALH84001. Maybe a crashed spaceship or
a monolith is buried in the Antarctic ice....