From Bazee only from reputed super sellers is fine imo, i've ordered tons from Ebay USA only from reputed sellers and never once had any problems, shipping or otherwise.
Rediff is reputed as well. So its upto the deal and price.
About 6600, don't go for it if you want music.
I forgot about E398 - You can easily go for this one, has everything, and just as cheap as k700 and 6600. One of the first mobile phones with music as its no.1 priority, has a good camera, has a very durable Java performance, can be flashed and flexed for better firmwares at home (that way you can add a minutes vid recording to it as well) plays videos, good looks and has some fancy club lights.
If you can't increase your budget then definitely its the pick over 6600 and K700.
Or just increase your budget and go for either k750 or 6630.
As for the ngage - i don't think Qdi really exists. QD is sucky anyways. The original Ngage is good as well with stereo speakers and is a handheld gaming console (with no new games now though) but its production has stopped and has no camera which you might be looking for in a mobile.