I'll say the Onkyo TX-SR805 as a great choice.
If you're lucky enough to find an Onkyo TX-SR805 (about $599 now), you should go for it. You can even find a used one for sale on line for about $399.
I personally own the 805, and I am more than pleased with it. By the way, all my speakers are rated 4-ohms, but they dip even lower! No problem to drive them at all with the 805. Plus you live in a house boat, so you'll never use all the power available of the 805.
Now for separates, as the above gentleman mentioned.
Well your best deal would be an Onkyo TX-SR705 (about $400 or just a bit more for a refurb) pair with an Emotiva UPA-7 ($599 list).
So, your total will be approximatively $1,000 or a fraction more.
Now between these two options, I will say that the 805 is still the best deal.
If you can find one for 5 or $600, I'll go for it.
The 805 amplifier section is very potent and it will drive 4-ohm loads.
It is THX Ultra2 certified.
It has Audyssey MultEQ XT.
It has very good Dacs, the TI PCM-1796A.
It contains premium parts all around it's internals.
It is build extremely well with a very big power supply.
It runs hot (so as the 705), but it's not a problem for me and for many other people. Plus it seems to not be a probem for you either. Plus you can put a smaller fan in top of the hot spot and just plug it in the AC inlet from the back of the 805.
The 805 is definitely a premium receiver.
Highly recommended.
There are several reviews of the 805 on the internet and from several reviewers of well known audio magazines. Just Google it. But I got a big feeling that you already did.
I don't know then if you've seen this one, it is more kind of a technical review, but still interesting nonetheless:
http://www.thefreelibrary.com/Onkyo+TXSR+AV+receivers.-a0178450770
Cheers,
Bob