Wich UPS to buy?

During winters there are a lot of power losses on my house. I am considering on buing an UPS.
However i don´t know wich UPS specifications i should consider. Do i have to also consider my computer PSU power?
I have looked to APC and Mustek, and Mustek seems to be cheaper for nearly the same specs.
Wich UPS to buy? Maximum cash 150€.

I would go for whatever is cheapest, unless you have the money to get one of those company like UPS that need a closet to fit into, these will all give you like 5min to spare to shut down and save your work.

I have personal experience with APC, and although its better than nothing I really wish they gave more time. I suspect Mustek will have relatively the same performance.

I got a PowerWare 5115 1400 va from e-bay several years ago new in the box for $156 US shipped, seller didn’t word the add well and it was the biggest one they made in that line :). Try to get one as big in the output watts as you can afford and make sure it can boost and buck voltage and filter the incoming AC.
My unit will run my PC with 5 hd’s, 5 optical drives, a 21 inch monitor and a TI 4200 on a AMD cpu board for almost 30 minutes. A small one like a 525 would be close to overload with this system and will probably run 5 minutes or less.
The big units have fans that run whenevr it is on battery or charging so keep that in mind if it’s in your sleeping area. The fan on mine is quite annoying when it charges the batteries for 2 days once a month.
If they have computer swap meets in your area sometimes you can get great deals on bigger older used units, just make sure the batteries are good or have been replaced recently as they are expensive.

I have a 19 ich CRT monitor and my PSU is 450W.
My system is:
Athlon XP 2400+
two hardrives
two optical drives
radeon 9000 Pro AGP 4X. I am going to upgrade to a AGP 8X card in the near future

PCI Slots ocupied with:

One SoundBlaster Live! Player 1024
One Silico Image 680 ATA\133 Controller

I think that the 450W on the PSU is the maximum power it can provide, i.e the system might be taking less power than that. Am i right?

I am considering a “Mustek PowerMust 1400 USB” wich costs around 150 € here at Portugal. Check this:

What do you think about it? Is it enough for my system?

That is as big as the one I bought and another APC one I got used later. It should run your system a long time when charged up, maybe 30 minutes as your monitor may not draw as much as mine and it looks like you have less drives. It would apear to be a good choice as long as your happy with the price and it has a good warranty and tech support, if needed.