forums or boards are being indexed more and more by SEs, although when it comes to PR esp google it appears its only done quartlety if your lucky.. i have both poetry boards (4 years old) and a poetry blog (barely 6 months old) ..the boards got a PR5 and the blog got PR6 .. my main blog Blogosphere Zoo (about 4 months old) got a PR3 -this time around .. to a blogger the Zoo would be much more interesting, though it was young and many backlinks have been added since the last google PR -cant wiat til the next PR ..lol
like everyone says here it all depends what your needs are and how you need to delivery your information and how you want your visitor to interact and offer feedback ..if your information is updated regualrly the SE monster will visit often whether its a board, blog or home page. keywords dont mean much if searchers dont use them to find sites, as for your site what keywords would you use to find it. with any site (product or service) there will only be 3-4 keywords that matter. I dont think the word RSS is going into increase your PR. also keep in mind theres a zillion sites out there fighting for top position and most the top ones are junk. go figure.
probably the most important question to ask is what do your visitors want NOT what the SEs want ..most of your visitors will come from outside advertising and word of mouth not SEs.. SEO-ing is a full time job by itself.
with all that in mind blogs are becoming very popular and are much easier to maintain ..bloggers like to surf ..board ppl dont – as far which will get the most unexpected traffic.