Hi Guy,
this is a slight departure but one solution which worked for me - I have the 18-70 and it isn't a bad lens at all, in fact providing you get a good copy it's a very good addition and decent general purpose walk-around lens but, at the wide end it's got quite strong barreling which is not ideal for wider shots of buildings etc or those which include people unless they are in the centre of the fame, which is why I never use it these days.
I shoot mostly people and purchased a s/h Nikon 20-35mm f2.8 D and it's a cracking lens even wide open with minimal distortion throughout and it is near as good as the primes which cover the 20-35mm range. I then purchased a s/h 35-70mm f2.8 D and it's superb too, again with minimal distortions and extremely sharp. The reason why these two zooms are so good is that they are 1.75 & 2x respectively so, they are more easily corrected for distortions during manufacture and are better lenses for working with people. Apart from the 18-70, I only own one other lens which is greater than a 2x zoom for the above reasons.
I also own a 50 f1.4, an 85 f1.8, a 75-150 Series E, 105 2.5 (manual) and 70-210 ( manual Series E ) - all are good copies but the three lenses I use mostly are the first two mentioned and the Series E 75-150mm f3.5, the rest I use as and when they would maybe do the job better. The SE 75-150 lens is excellent and can be found dirt cheap and the copy I own is very sharp even wide open - these three lenses cover most of my needs.
As to your needs - you have not yet purchased a DSLR and the D50 is a nice entry level and excellent choice camera. However, if you are buying into a system for the first time, then I would advise you to look ahead and purchase only lenses which are suitable for full frame cameras rather than DX format as I'm quite sure once you have the DSLR photography 'bug' you will eventually go for a FF camera when they become cheaper which they eventually must!
Buying S/H can be scary and fraught with risks but I've done ok and if you find that a lens doesn't quite fit your needs as you progress, if it's a good quality lens like my 20-35 or 35-70, then one can re-sell with virtually no finacial loss as they are sought after lenses.
If you intend to shoot dramatic & wide landscapes then either a 10-20 or 12-24 is a good lens to purchase but for starters & general use and if your budget allows it, I would skip the 18-70 and put the money towards a used 20-35 f2.8 D and a 35-70 f2.8 D ( which does have a macro facility at the wide end). These two will cost only about 40% (-ish s/h) of the highly sought 24-70 and give slightly wider coverage with little difference in IQ. You can then add your 70-300 VR which will give you a good start to meeting your needs. As there would be no need for a 35mm if you went down that route, you can also put that money towards one of the others I have suggested.
Other lenses such as the ultra wides can then be purchased as and when you feel they are needed. Lenses are generally seen as long term investments while camera bodies are seen as shorter term purchases - a good lens can last maybe 20-30 years if looked after so it's better to start with good lenses and upgrade bodies as they become obsolete or wear out. While DX lenses will be ok with your D50, in the long term, lenses suitable for full frame will be more practical and better purchases and reduce any financial losses through upgrading to a minimum. Also, don't be affraid of looking at older manual AI or AIS lenses - there are some bargains to be had. At the end of the day, it's you who will be using the lenses and while others such as myself can offer their personal views, in the end it's down to you to choose those which best fit your needs.
Regards...
Tony
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