I'm usually an incorrigible lurker on lists like this, but
since this project is particularly interesting to me, I
thought perhaps I should introduce myself.  I've used
Haskell on and off for years, but I still consider myself
something of a novice at it.  At the same time, I'm a
fan of IDEs for software development, but most of the
Haskell community seems to use emacs or vi.  I've
written a few Eclipse plugins (never published) and
I like using it.  So perhaps I can help.

My first question:  I've been using the Haskell plugin
for several weeks now, and I find that interacting with
ghci is awkward using the console view in Eclipse.
For example, outside Eclipse in ghci I can scroll
through commands already entered using the up and
down arrow keys; inside Eclipse they don't work.  
When I start up ghci in Eclipse, it usually can't find any
imported modules, because the default directory is
always the eclipse directory.  I have to change
directories by hand to the src directory that my code
is in.  And there are other little gotchas as well.

My question is:  what are your plans for ghci interaction?