I know where you're coming from, Aquarius. I could so easily spend hundreds of dollars on books--that is one of the reason I have to limit my time browsing on Amazon.com. It is just too dangerous to visit often!
Speaking of Amazon book purchases, one such purchase was a copy of Posthumous Keats! I devoured that book back in April or May; it is an interesting and, I think, worthwhile addition to a Keats collection. It's the study of Keats's fame (how various people have seen his fame) written in a circular style, so different points in his life are touched on several times from several different "directions". It is in many ways the meditation of a poet on a poet. I wouldn't recommend it for people who are *very* new to Keats (i.e. have only read the Wikipedia bio and read an Ode or two), but for any Keatsian who's read at least one of the cannon biographies, and most of Keats's poems and letters, it is a great read. It has been a while since I last looked at the book, so I can't give any detailed review. Suffice it to say, I think it is worth the purchase, especially if you're getting it in paperback; only the hardback was available when I bought it.
I agree with you about Severn's portraits of Keats. They don't capture Keats's intensity or strength of body (or character) very well. The one exception I would make is the deathbed sketch. While not a portrait per se, it intimately captures Keats in such a vulnerable, human moment. It seems so much more authentic than Severn's other renderings because it wasn't done to display in a gallery or sell or to keep up Keats's posthumous fame. . .it was simply a sketch to keep Severn awake. It is perhaps Severn's least self-consciously drawn portrait, and therefore the most authentic.
As far as the picture I would like to have in poster form--I'd say far and away my favorite is the Haydon sketch done for Christ's Entry into Jeruselem. Keats looks like an energetic young man with a sense of strength and vitality about him--not at all like the Severn portraits that try so hard to capture in him what the great poet "should" look like. In addition, his mouth (showing his protruding upper lip, which was a hallmark of his features) has a sense of energy and urgency about it--but not flying out in all directions; it is a honed and purposeful energy. This sense of controlled energy reaches his eyes, which contain a steady, intelligent gaze of the like that certainly would attract others to want to know more about him. It is an expression that is thankfully lacking in the dreamy, dewey-eyed sentimentality that Severn seemed to think a Poet would possess. In the Haydon sketch, I can see both the practical, detail-minded medical student and the visionary poet. I see a man at the beginning of a journey--going down a road he chose, himself, to travel. The look in his eyes very much reminds me of On First Looking into Chapman's Homer; Keats the poet is not gazing unfocused and half in dream, he's much more like an explorer who has just spotted a new world that he is about to name.