Base your blinds on how long you want the tournament to run. Whenever i structure my blinds, i always do it based on how many tournaments i want to run that day, how long i'm willing to let it run for, and how aggressive i want the action to be.

If you want a long game, 25/50 is very high for 1000 starting chip count. If you sat the game and just called blinds to fold, you would last only 20 hands, but it may be less since the blinds increase as time goes by.

The rule of thumb i use is that the tournament will end shortly after the big blind equals to or is close to the starting chip count. I've alwys used this method and it has yet to fail me, despite the number of players.

For example and using your 25/50 blind structure, if i wanted to play a 2-hour-or-less tourney, i would start people out with 3000 chips and up the blinds every 15 minutes like so:

25/50
50/100
100/200
200/400
400/800
800/1600
1600/3200
3200/6400

I usually get at least 8 people, so by the time it gets to two people only, there's a total of 24000 chips in play among the two. If the blinds are still small, it will take forever to end. I structure it this way because i don't just run 1 tourney, i usually run a few all at once after each other.

I usually host lower buy-ins with multiple tournaments so there's more playing (since that's what we pay for... to play and not bust out after the 3rd hand). If i do ever get some people that's willing to play $100 buy-in, of course i'll adjust the blinds to last a bit longer to let it play out so we can all get the perfect hand or the NUTS.

Hope this helps... i guess it's up to you, it's your tournament.