My choices are similar to Boromir's only for different reasons in some cases. As a confirmed elf-fancier, Rivendell and Lorien chapters are favourites partly because of the information they provide as well as becasue they provide a respite from the extreme tension of the chapters that precede them.
As for the Window on the West ... well Faramir is just Mr Wonderful isn't he? But having extolled his manifold virtues on the CbC I will restrain myself here ....
A couple of other favourites, not yet mentioned, are "The Last Debate" & "The Steward and the King". These chapters are so rich..
The Last Debate starts with one of those rare passages that show Gimli and Legolas' as more rounded characters. They are representatives of their fading races at a turning point in history - the time of men and their presence is not required at the debate. And for all that it is Gimli that "stalks" and Legolas sings... it is Gimli who is initially the more positive "When Aragorn comes into his own" opposed to Legolas' if....
Then there is the glimpse of the history of the Lords of Dol Amroth - the evident nobility of Imrahil indicating perhaps the effect that an influx of far more noble elven blood will have on the lords of Gondor in the age to come. Then as Gimli, Legolas and Merry and Pippin catch up we get not only the history but further insights in to character and a reminder that the Nine walkers were truly a fellowship. Finally the debate itself which mirrors the council of Elrond (albeit in a rather more macho fashion) as it leads to the inevitable, desperate resolution.
The Steward and the King After all that testosterone ... I have to confess a weakness for soppy films and *snivels into handkerchief* Faramir's wooing of Eowyn is just so beautiful......time halted, hair mingling raven and golden... *gulp*..oh and if that wasn't enough it has the crowning and stuff....
Finally though hit has already been mentioned, the last pages of the "Grey Havens" is just so moving and at times reminds me of Bunyan's bittersweet farewells in "The Pilgrim's Progress" (Mr Standfast " I see myself now at the end of my journey, my toilsome days are ended..." and Mr Valiant-for-truth crossing the river