I think you do need the jhanas as they are samma-samadhi (right
concentration) and a factor of the Noble Eightfold Path, but perhaps
they don't need to be specifically developed for the realization of
Nirvana...in the dry insight method, I suppose the time when the
meditator attains the path and fruit, the supramundane consciousnesses
(lokuttara cittas) that arise then constitute the first jhana. (I hope
I said that correctly, check out the Abhidhamma:
http://zencomp.com/greatwisdom/ebud/abhisgho/abhis01.htm)
There are two methods of meditation that I know of:
1) developing both samatha (calm) and vipassana (insight) meditation
2) developing vipassana meditation alone ("dry insight").
Obviously some calm is needed to progress in the dry insight method as
well, but what is referred to as "samatha meditation" in the first
method is meditation that is specifically developed to attain the
jhanas, leading to the attainment of supernatural powers (abhinnas).
So samatha meditation, or developing the jhanas, isn't needed in the
second method. Vipassana meditation is essential for the realization
of Nirvana, however, regardless of which path you follow.
(http://www.lawofkarma.net/lptong/diff.html)
Vipassana meditation based on the four foundations of mindfulness is
supposed to be the quickest route to Nirvana
(http://www.lawofkarma.net/lptong/vipassana/howto.html). I have no
idea why the Buddha didn't emphasize it more in the Tipitaka...and I
have nothing against the jhanas either. I personally practice the dry
insight method, but I want the jhanas as well sometimes in the future.
There are currently two great meditation masters in Thailand who teach
the dry insight way:
1. Ven. Ajahn Tong (http://www.lawofkarma.net/lptong/index.html)
2. Luang Paw Jarun (http://www.lawofkarma.net/lpjarun/index.html)
I would suggest visiting them if you are interested in the ending of
suffering.
If you are interested in the jhanas, Ajahn Brahm in Australia is a
great teacher (http://www.bswa.org)
I totally understand the debate. I think it more depends on your karma
which path you follow...and perhaps the aspirations you made in your
previous life/lives?