certainly the d7000 i think u have been misled . The D7000 sits above the D90 in Nikon's current lineup, and as befits its new position in the range, the D7000 combines elements of the D90 with elements of the D300S The most obvious physical clue to its new position is a magnesium alloy body shell, which up to now has been reserved for Nikon's top-end APS-C and full frame cameras.
'Under the hood' though the differences are legion - a new 16.2MP CMOS sensor, dual card slots, a new 39-point AF array, 'true' HD movie mode with full-time AF and more customization options, some of which are inherited from Nikon's professional DSLRs.
they decided to make the d7000 become much more professional . i especially like the dual card slots and also 100% viewfinder coverage which u get only in top range cameras
as for low light performance it doesnt give crappy pics at all
if ur worried about the lenses - Like the D90, the D7000 supports AF with Nikon's older AF and AF-D lenses (lower-end models are limited to compatibility with AF-S and AF-I optics only) but additionally, because the D7000 has an Ai indexing tab on its lens mount, up to 9 'non-CPU' lenses can also be registered with the camera.
This allows the use of virtually any Ai specification or later lens to be used in aperture priority or manual mode with the D7000, with almost no loss of functionality (apart from AF). Novice DSLR users might never look beyond the horizons offered by their kit lenses, but for the enthusiast, legacy support like this could well be a deal-clincher.