First, regarding the monitor, I assume you mean that the end of your
monitor's power plug has the shrouded AT-type connector. Whatever you do,
don't let *that* drive your PSU decision! You should be able to fix that
with a simple adapter!
Here's an example of an extension cord for that type of monitor:
http://www.directron.com/monpowcorwco.html
I'm using this only to clarify that you indeed have this type of connector,
the end of your plug probably looks like the shrouded end of that extension,
correct?
Since that is an AT style power cord intended for an AT style PSU, you're
not likely to find this on any new ATX PSU. I wouldn't say impossible, but
I haven't seen one in a loooooong time. But again, that should be a trivial
thing to fix w/ an adapter/extension:
http://www.digiconcepts.com/cables_power_06.htm
http://www.digiconcepts.com/cables_power_08.htm
Not sure what's available in the UK, but any decent computer store should
have something similar. The last thing you want to do is having something
silly like the monitor's plug restrict your PSU selection.
As far as the PSU itself, I'm a big believer in the Antec TruePower line.
It has one feature that is quite unusual. Normally, the spec'd power output
(let's say 350W) is divided among the various "rails" (3.3v, 5v, 12v). The
way the power rating is calculated is based on summing of all the MAXIMUM
power available across those rails. For example, let's say PSU "X" (350W),
and supports a maximum of 200W on the 12v rail, 100W on the 5v rail, and 50W
on the 3.3v rail. You add them up, you get 350W! The key point here is,
even though you have a 350W PSU, you're always limited by the maximum on any
given rail. So suppose you have nothing using the 5v and 3.3v rails (not
realistic, just keeping it simply for illustration purposes), but have
exhausted the 12v rail's 200W w/ all your HDs, optical drivers, etc. Even
though you have 150W of reserve power over the other rails, it's USELESS to
the 12v rail. You can't add any more 12v devices, even though you have 150W
of reserve power untapped!
The Antec TruePower line of PSUs don't work this way. When it says 430W,
that 430W is available to ALL the rails! That's why it's called
"TruePower", get it?
http://www.antec-inc.com/us/support_productInfo_details.php?ProdID=20430
If you follow the above link, go to the bottom, on the FAQ, #3, it basically
is describing this feature, comparing the TruePower line to their other
economy line (SL Solutions) w/o this feature.
Of course, it makes for a more expensive PSU (mine cost $80 US on sale).
But I'm a big believer in not skimping on the power supply. Once your
system is underpowered, or isn't being supplied a strong, steady stream of
power with few fluctuations, everything else becomes suspect once problems
creep in. If I had to, I'd rather buy a smaller Antec than a larger
non-Antec model. IOW, I consider 430W a nice, middle-of-the-pack choice
among the Antec TruePower line, but if I found the 430W too expensive, I'd
drop back to 380W before looking to another brand w/ 430W. The fact that
ALL the rated power is still available on ALL rails makes this much less of
a problem/concern.
http://www.antec-inc.com/us/pro_powerSupply.html
Basically, the TruePower goes from 330W to 550W. For most people, the 430W
is perfect. To save a little, the 380W would be fine too, heck, even the
330W will outclass most standard 380W models. If you're really in economy
mode, the SL series is good too, it just doesn't have quite the same
features. But all the Antec PSUs are VERY well built and perform well.
The only other brand I highly recommend is the Enermax line. Very well
built too, I have a 350W model myself (
http://www.alienrock.com/enposuegf350.html ), in my wife's PC. It's not for
gaming, and isn't all that heavily loaded anyway. It performs flawlessly,
but again, doesn't have the features of the Antec TruePower I described
above. For gaming, I'd probably go a little higher, maybe 380W or so.
But if you ignore all this advice and simply go for something else, I would
not go below 350W, ever, at this point, 350W is my bottom. Every day the
power demands get greater and greater. Intel only recently introduced the
Prescott P4, this darn thing is already requiring 20-30% more power than the
last model! Everyone who is running Intel and already marginal on power
will be in for a surprise if/when they decide to upgrade.
HTH
Jim