Please spend my money.
 

Right, i have a Nikon D40 with unstabilised 18-55 kit lens. Sigma 70-300mm apo dg Macro f4-5.6 non stabilised. and a manual focus Nikon 50mm 1.8 prime.
Jessops afdn flashgun.

I have upto £1500 to spend on a new camera and lenses, i want to keep my existing camera and lenses so the camera and lens must be compatible with my existing d40 and lenses (focus motor in lens). I have been leaning towards a d5100 over the d90 (i know the d90 has a pro layout) as i prefer the movable Lcd and exellent high ISO performance and better sensor, with a stabilised 18-55 kit lens £530 and the Sigma 70-200mm f2.8 os dg hsm £900.

The problem i have with my kit is slow lenses very poor in low light without flash and a 2.8 with vibration reduction will go a long way towards solving the problem also my d40 is showing its age now.

What would you buy in my situation (mainly candid people photography)
Thx in advance.

A d5100 will be a huge improvement and upgrade over the d40. I was in a similar situation a few years back, but I had the d60. I opted for the d90 and still use it today as a back up to my d300.

The d90 is still a very capable camera, I still use mine a lot as its lighter and smaller than the heavy d300. Plus the sensors are the same and handle high iso noise in similar ways.

If I was in your position I'd go for the d7000 over the d5100, they have the same sensor but the d7000 has much more going for it with weather sealing and an auto focus motor in the body. This opens up a lot more options as far as lenses are concerned. If you went that way lenses like the stunning Nikon 80-200 2.8 would be an option.

The D7000 at £709 and 80-200 £739 yes thats within my budget but id miss lack of stabilisation typicaly 2.8 offers 1 stop improvment whereas VR offers upto 4 stops.

Ok first let me confess I'm a Canon man.... ok now thats out of the way...

Now I used to think the same way, and in fact bought Canon's 24-105 f4 because of the IS... and dont get me wrong its a great lens but IS wont stop motion & IS wont blur backgrounds so about 12 months ago I bought the 24-70 f2.8 (no IS) and while I still have the 24-105 I havent used it since and must get round to putting it on ebay.

Ok if you can afford f2.8 and IS - go for it, otherwise Id go for the faster lens every time

Would be nice to have the VR, but with the 70-200 2.8 afs vr running to a £1000 more, or there abouts, the vr can wait. Plus I have never had any image stabilization so don't missed it.

I suggested that lens and body to fit your budget and you'll be hard pushed to beat it In my opinion. The 80-200 is an amazing lens and with good technique who needs VR.

The Sigma 70-200 2.8 OS can be had for £900 at digitalrev i cant afford the Nikon glass, and reviews say the Sigma is not a million miles behind the Nikon.
I am thinking about the D7000 body only only thing is it takes me a little above my budget and i really want the 70-200. Im sold on the 39Af points over the d5100's 11 and faster continous shooting along with the build quality and my 50mm 1.8 AF which is manual focus only on my D40 i would be able to focus with the D7000, the d5100 has the same great sensor of the d7000 and a movable screen which i could really use, i'm really stumped which to go for.

I'd say the sigma is probably a good lens, but not even close to the nikon. there's a good reason the pros all use the Nikon over the sigma or tammy. Yes the 70-200 2.8 afs vr is expensive, but for a good reason.

The 80-200 2.8 two ring, is a heavy duty pro lens, which was the equivalent to the 70-200 in the film days, it works great on a digital body as long as you use good technique [which applies to all long telles] and give yourself space.

Of cause you would need the d7000 for the motor.

I bought my 80-200 used on eBay for £500 and payed fixation to service it and fix the af ring. Cost £160. The lens is like new.

I'd seriously consider this lens.

Sigmas tend to be soft unless you get a good copy. Sigmas quality control is notoriously shoddy, so if you are going to buy one I'd go to ashop and try it first.

I'd save the extra money and plumb for the d7000, you will only kick yourself after I'm sure. The extra features are worth every penny IMO.

Go for the Nikon D7000. Forget the moveable screen which you will never use, the amount of people that buy the camera for that makes me laugh as it almost never gets used. The D7000 is a stunning camera, far better than the D5100. Its nicer to hold, has a better ISO range, is magnesium plated so is better made and gives many more far more expensive cameras a bloody nose. I had the choice a long time ago of the same and im so glad I went with a D7000. Don't forget you get a motor so can get more out of your lenses which you wont with the D5100.

I did a course with a guy that had one and I with my D7000 had superior shots in all cases. He didn't even have a bulb mode for long exposure settings, I did. On paper they are similar but in reality one is a good mid range consumer camera and the other is a great all round semi pro piece of kit that many professionals are using as a back up camera.

Good luck, whatever you decide!

Put another way, if you go for the D7000, you wont need to upgrade very soon but if you go for the D5100, its more likely you will. Also in terms of lenses, forget the 18-55. Just go for an 18-300 and a better 50mm F1.8, of you could go for the £70-300 VR, or buy the more expensive 18-300 and have everything covered. You will come in on budget and have a stunning piece of glass and a great camera. I can promise you now that you wont keep the D40 after you get the D7000.