I'm not able to tell if the 70-300 is the G type or ED???
70-300 G is said to be less sharp than the ED and the ED is just acceptable.
Also you will not have the wide side covered. you could still need a wider lens for indoor shots also none of the above is a fast lens so you will endup with 2 slower lenses and no VR to support them. This could be ok if you will be using flash. You will need to buy an external flash at some time however to cut down the expense at the initial stage I would rather go with something that gets away without high light demand.
For that yo uhave lots of options and it's a matter of personal preference to decide on which to get:
- fast lenses (zooms or primes) ie lenses witha wider aperture (down to 2.8, and even 1.4): those are the best glass usually used by professionals and as you might have guessed really expensive stuff. However a minority of those is fast, sharp and still affordable 50mm 1.8 sells for less than 100 usd new, the 1.4 version is around 3 times the plus but believe it or not for what it offers is still considered cheap. You could go with the 1.8 version: fast lens, great for portraits and shots of the fish without flash and sometimes without tripod, it's what I mostly ues at aquarium visits, especially if flash is not allowed. if I can use flash, coupled with this lens I get perfect results.
- Fast non nikon glass of that I will mention the Tamron 18-50 and Sigma 17-55 these are still considered fast and sharp enough, would not give the same sharpness of nikon glass but still come a t a fraction of the price. I never used any of those and therefore suggest you make yoru research on them if yo udecide to get any of them in the future.
- Slower Nikon glass: the Nikon 18-70 Kit lens (I prefer to have it over the 18-50) is considered very sharp and can be gotten at a great price when you buy it with the body. at a maximum zoom of 70 you can shoot at shutter speeds of 1/70 which does not exist on the camera so basically 1/80 or 1/60 or 50 if yo uhave stable hands. this speed can be achievable with acceptable light levels and boosting the ISO. The school of thought on this is that yo ucan getaway with longer exposure times with shorter lenses.
others (Me included) prefer to have a faster lens even at hte wider area or have VR at that side of the zoom. that's where the 18-200 VR comes in. it might sound a bit expensive at around 700 usd if yo umanage to find it but still it's a multiple solution:
wide lens for scenery or use for indoo shots. acceptable zoom for wildlife (maybe not birds) fast focus. convenient for frequesnt travelers as I traveled on many instances with just this lens. then a set of extension tubes or cheaper yet a set of closeup filters allows me decent macros with autofocus and metering still possible. also this lens allows yo uto manage any scene without need for changing lenses which is combersome and leeds to missed shots sometimes as well as more risk of introducing dust to your sensor. and above all VR II which allows you to shoot at 4 times slower shutter speeds.
Some others would prefer an 18-70 that they buy with the camera for a cheap price and then couple it now with the 70-300 VR which is much sharper (Never used it but that's what it's reviews show) than the G or ED type and still sharper and cheaper than the 18-200 in addition to offering a longer reach.
Adition of a Kenko 1.4 Teleconverter on this lens is possible which gives you a 420 mm lens (at f 8 so good loight is necessary which is usualyy no big problem for wildlife) this provides a longer reach handholdable solution that gives accepable results at a fraction of the price of the high zooms.
Basically you have lots of options to consider and believe me chosing the body is much easier than the lenses, you will have to consider your shooting style and your budget and act from there.
The cheapest solution with good value for now would be to get a good deal on a used D50 or 70s with it's kit lens and use it for a while before buying a (faster lens for portraits, a longer zoom for wildlife, a faster lens for low light, a macro lens.... according to what yo usee you're missing most)
One more expensive solution that would allow you to go for more time without getting anything would be the body + 18-200 VR.
Keep us informed on what you chose