I need help choosing a PSU.  My current one, an Ultra 400W, stopped working.   I would like an 80+ PSU and one with modular cabling because I have a small uATX case.  THe extra cables get in the way of good airflow.
 
My current rig:
 
AMD X2 5000+ BE OC to 3 ghz @ stock voltage
2 x 1GB DDR2 800
ASUS M2NPV-VM (Geforce 6150/nforce 430)
1 x 7200 rpm Seagate SATA
1 x 7200 rpm WD PATA
1 x DVD burner PATA
 
I would like the new power supply to be ok for upgrades in the future maybe a year or so.  Today the new rig would look something like:
 
AMD Phenom 9750 or 9850
Mobo with either AMD 780G or Nvidia Geforce 8200/8300
1 x AMD 3870 or Nvidia 9600 GT
2 x 2GB DDR2 1066
2 x 7200 rpm SATA
1 x DVD burner PATA
2 x digital TV tuner cards
 
I am thinking somewhere between 400 and 500 W but I am looking specific recommendations.

I'd go for either:  
http://www.newegg.com/Product/Prod [...] 6817341010
$54.99 after rebate with free shipping,  
 
or: http://www.newegg.com/Product/Prod [...] 6817151040
$72.99 with free shipping.
 
If you want to future proof a little: http://www.newegg.com/Product/Prod [...] 6817703005
$89.99 after rebate with free shipping.

I would go with a Corsair HX520 or choose from below:
 
Top Tier PSU:  
http://www.tomswiki.com/page/Tiere [...] ngs?t=anon
 
http://www.xtremesystems.org/forum [...] p?t=108088  
 
http://www.jonnyguru.com/forums/showthread.php?t=1460
 
Silent PSUs
http://www.silentpcreview.com/article699-page1.html
 
AMD Certified PSUs (Single+Crossfire):
http://ati.amd.com/online/certifiedpsu/index.html
 
Certified SLI-Ready Power Supplies  
http://www.slizone.com/object/slizone_build_psu.html

80+, modular:
 
Corsair 520HX
Antec NeoHE/Neo Power 380/430
Enermax Liberty 400/500
Enermax Modu82+ 425/525
Seasonic M12/M12II 430/500
 
All are excellent choices.  The Corsair 520/620 and Enermax Modu82+ PSUs are raved to be the most silent PSUs around.
 
http://www.silentpcreview.com/article699-page1.html

^ Exactly as he said.

Prices on the corsair hx520 seem to be pretty good.  You can get it for $80 after rebate from buy. com http://www.buy.com/retail/product. [...] 0716&loc=0 .
 
I guess the only question is 520 W overkill if I am not planning on doing SLI or crossfire?

Not overkill at all, you'll hang out comfortably within 50-60% of the capacity of the power supply and should have a long life, low noise, and besides, that's where a PSU is most efficient.

Sounds great...thanks

You get the Corsair 550VX for $70 at buy.com ......... thats a stellar deal too.....unless you have to have modular.

I just picked the modular because I have a small uATX desktop case and I want minimize the number of cables in it for better airflow.  Speaking of airflow do all know of any good fans that fit in a 5.25"or 3.5" bay.  This one from Vantec looks interesting but kind of expensive.  http://www.newegg.com/Product/Prod [...] 6817122110
 
I currently have an Ultra Microfly case and things are really packed in there.  
http://www.ultraproducts.com/produ [...] ductID=441
I imagine the heat is going to shoot up once I add a video card.

Do not buy anything Vantec, especially a radial fan (unless you like noise and short bearing life).
 
Just replace your rear fan with this:
Scythe S-FLEX SFF21F 120mm Case Fan - $20
http://www.newegg.com/Product/Prod [...] 6835185006
 
Heat and noise should not be [much of] a problem with that small change.

Could part of my problem with airflow be that I am using the fan headers on the mobo?

I'd just replace it and run the SFlex at full using the included Molex->3-pin adapter.  That's no substitute for good quality fans.
 
To answer your question, maybe.  Check what the Ultra website says about it's rated RPM, then check SpeedFan or Everest or whatever to see what the actually RPM is.  If it's lower than rated, yes, it will be pushing less air than if it were running full speed.