If you're looking to buy expired domains for not too much I have to say here on Acorn is pretty good
People offer strong domains fairly regularly
Buying blind because a domain may have 1 link from the huffington post seems silly to me.
Yeah I think it depends on how you look at SEO - if you look at it in the old fashioned way then it doesn't make sense.
For me, with all of the Google link penalties I thought "ok, so what I need are fewer links with much more power, but what links would those be?"
Since PR isn't updated anymore, and was open to manipulation, i.e. you can see it, the spammers can see it, and so in their eyes they try to get links from pages / sites with PRX and above, then what other measure might Google use, that isn't promoted and isn't easily measurable.
I thought a better way to think of it might be "if I could have a link off anyone, who would I love to get a link from?", and that made the process a whole lot easier - I'd like the BBC to link to me please, in the top 100 sites in the world (Alexa), unspammable, can't buy links from them, don't advertise, don't try to manipulate rankings, etc.
In Googles eyes they are prefect - can be 100% trusted, have 100% reputation, authority, etc.
Since the olny way to get that link is to buy a domain with an existing BBC link and use that to link to my sites (in some way or another) I did that.
So I bought some domains that have BBC links (and have since bought some others with CNN, proper .gov's, etc) and the results have been great.
I think it works, I think you need to look beyond the "huff post link" - if you still measure the value of a link by PR, TF, CF, DA, PA (which let's face it, Google DO NOT use those measures) then you are going to struggle, and I guess it's a footprint too, if your links all come from high PR/TF/CF/PA/DA etc pages / sites.
I think when you hear Matt Cutts banging on all of the time about trust, authoirty, reputation - that's what Google want to rank sites on, but there is no active measure of those values that we can see, so you have to read between the lines and see if you can find a fudge that is likely to satisfy those criteria - and what better than the best news sites in the world that don't do advertising, etc?