Canon Rebel XS 10.1MP Digital SLR Camera with EF-S 18-55mm f/3.5-5.6 IS Lens
# DIGIC III image processor provides fast, accurate image processing; Live View Function
# EOS Integrated Cleaning system and Canon-designed Self Cleaning Sensor Unit, plus Dust Delete Data Detection in included software
http://www.amazon.com/gp/product/B001CBKJGG?ie=UTF8&tag=bestdeals-y-20&linkCode=as2&camp=1789&creative=390957&creativeASIN=B001CBKJGG

DSLR with HD video can consider
Nikon D5000 12.3 MP DX Digital SLR Camera with 18-55mm f/3.5-5.6G VR Lens and 2.7-inch Vari-angle LCD
# D-Movie Mode with sound; record 720p HD movie clips
# Vari-angle color 2.7-inch LCD monitor; one-button Live View
http://www.amazon.com/gp/product/B00267S7TQ?ie=UTF8&tag=bestdeals-y-20&linkCode=as2&camp=1789&creative=390957&creativeASIN=B00267S7TQ

And if you want a point and shoot camera then can consider
Panasonic Lumix DMC-FZ35 12.1MP Digital Camera with 18x POWER Optical Image Stabilized Zoom and 2.7 inch LCD
http://www.amazon.com/gp/product/B002IKLJU0?ie=UTF8&tag=bestdeals-y-20&linkCode=as2&camp=1789&creative=390957&creativeASIN=B002IKLJU0

It is amazing. All of its features are stunning, quality ( better than i thought )
its mint, warranty still 3 years. Its amazing. go for a nikon.

At the price break you mentioned, only a couple of DSLR cameras which can use the lenses you need are still being sold. If you are lucky, you may be able to find a new Nikon D40 with 18-55 mm lens for under $450.

To shoot the water droplets with it however, you will need a macro lens … an additional $530 and to find a DSLR that will shoot video at 1080i, not 1080p, you are looking at cameras that cost closer to $850, body only.

It seems to me, you have decided what you want in the way of a camera based upon some specifications that seem to be the "best" and then placed figure on it based upon what you are willing to pay or what your budget is.

Spend some more time looking. If you really want to spend time shooting video, you will need a proper HD video camera that has built-in SMPTE time code and genlock embedded in the video, so you have half a chance of being able to edit the resulting video

Here is once such video camera.

http://catalog2.panasonic.com/webapp/wcs/stores/servlet/ModelDetail?displayTab=O&storeId=11201&catalogId=13051&itemId=274232&catGroupId=112502&surfModel=AG-HMC150

As you will learn, the video feature found on DSLR’s are compromises and bring with them the same issues found when attempting to create video using a P&S camera. They are fine for YouTube, but not for prime-time.

One other issue you may want to consider is the 24 fps rate used by motion pictures and 30 fps rate used on television.

Those who are shooting video now are leaning toward cameras that can shoot at the 24 fps rates. Only Nikon has such a rate on their DSLR cameras with video but they "only" shoot at the more common 720p format.

Canon has some cameras that shoot at 1080i, but at 30 fps.

You will need to do a lot more research before spending a dime it seems.

Anyway, you would need a camcorder or get Canon SX1, which can do 1080p and has 20 optical zoom, but image quality is so so.

Sony HX1 is also good choice worth a look.

However, if you really want HD video, you shoud save more and get Pentax K-x that can take HD 720p video at 24fps.
http://www.amazon.com/gp/product/B002OEBTC8?ie=UTF8&tag=computer0bd-20&linkCode=as2&camp=1789&creative=390957&creativeASIN=B002OEBTC8