Yandros, this is an oft cited argument. However, noone in their right mind would pay those prices for the Sony lenses - they may be RRP and they may sell for that in places like Jessops, but that's merely a side effect of being a new camera company. Check out the US prices - already slashed in the big retailers. To give you an idea, the RRP for the Zeiss 135 1.8 is £1100, I paid £650 to my door.
I'm not going through all of those, but let's show you quickly what you can get each for - all prices delivered from reputable suppliers:
Sony 16-80mm F3.5-4.5 ZA Vario-Sonnar T £549 - actual price £350
Nikon 16-85mm AF-S DX f/3.5-5.6G ED VR £429
Sony 100mm F2.8 Macro (D) £599 - actual price £350
Nikon 105mm f2.8 VR Macro £498
Sony 70-200mm F2.8 G £1759 - actual price £1100
Nikon 70-200mm f/2.8G AF VR £1148
Sony DT 18-200mm F3.5-6.3 (D) £349
Nikon 18-200mm f/3.5-5.6G AF-S DX VR IF ED £450
These are not like for like - the Nikon is a better lens. The 18-200 has also been replaced by the 18-250.
Sony DT 75-300mm F4.5-5.6 (D) £175
Nikon 70-300mm f/4.5-5.6G AF-S VR IF £330
Again, not like for like - the Sony is a budget kit lens that really goes for around £120ish. Look to the new Sony G for a fairer comparison.
Anyway, here's the counter argument:
Sony - Sigma 20mm 1.8 IS - £180 2nd hand
Nikon - doesn't exist
Sony - Minolta 35mm f2 IS - £150 2nd hand
Nikon - doesn't exist
Sony - Minolta 50mm f1.4 IS - £125 2nd hand
Nikon - doesn't exist
Sony - Minolta 58mm f1.2 IS - £100 2nd hand
Nikon - doesn't exist
Sony - Carl Zeiss 135 f1.8 IS - £650 new
Nikon - doesn't exist
And then we've got the huge argument of:
Sony - Sigma 70-200 2.8 IS - £600
Nikon - Sigma 70-200 2.8 IS - doesn't exist
and that list goes on for a lot longer