[Azathoth]

Time for my 2 cents.

Buy the products that fits your use case for best results.

I wouldn't bother with I2 style NVG setups for those conditions. You can home brew a digital night vision unit from a camcorder for ~300-500 dollars and will serve you as well since:

1) you are indoors and the place is filled with IR light sources
2) it's far cheaper and you're not going to really use it in any meaningful way,
3) its easily disposable and if gets shot out Who cares.

I think Ben suggested it above somewhere. If you like what you are getting and want to start using NV outdoors you'll want to consider replacing that with someone completely different. unless you are on a well lit paintball field at night.

Usage / budget drives what you should be considering to purchase. If you are taking night sky photography through a high power telescope a 'tactical' grade tube is not necessarily ideal.