Which combo is the most attractive at the moment?
- The components should run together without much configuartion.
- no overclocking!
- silent
- reasonably cheap
- CPU: AMD Phenom IIX4 955 or something close to this
- 8 GB RAM
- mainboard: USB 3, SATA 6 Gb, graphics onboard, passive cooling
- CPU cooler: silent, cheap
Motherboard,
Well that depends, do you want one with/out an IGP? If you desire one with an IGP check out boards with the 890GX chipset if not then the 890FX might be the pricier way to go… I'd say since you have no desire to OC or run dual gfx cards(GX has 22 PCIe lanes and thus only supports x8 + x8 configuration vice the FX's 42 lanes which supports x16 + x16 - which isn't necessarily a bottleneck unless running top tier cards) you should go with the generally cheaper 890GX board. I'm partial to Gigabyte, Asus and to a lesser extent MSI(TBH before Abit and DFI went under I strictly bought their products - it was a love hate kind of thing ><).
Gigabyte GA-890GPA-UD3H or Asus M4A89GTD PRO/USB3 look pretty good… Oh and there are also mATX options too if you're going for a SFF(small form factor) build. Oh and if you like or prefer Asrock, Biostar or Foxconn(they tend to be cheaper - then again Foxconn is a massive OEM and produce just about everything, Apple/Nintendo/Cisco/HP/Intel/ect, so it makes little sense to knock em) they'll work fine too… I only avoid ECS.
CPU,
Stateside, and going off newegg, you can get a hexa-core AMD for somewhere between $170 and $240 depending on clockspeed. Starting with the quad 955 and going up to the 975 you get em for $140 to $200. So it depends on whether you want the "future proof" 6 cores or slightly faster(clock speed) slightly cheaper 4 cores. If you can rationalize the greater expense I'd go with the 1090t. If not the 955 or 965 will do the job too. Especially considering the bulk of desktop applications are still only single threaded(IE adding extra cores doesn't help - save for multitasking, but 4 cores is enough for that).
RAM,
Since you have no inclination to OC, all you should consider is the price, warranty and companies CS/RMA track record in your country. I guess if you want improved synthetic benchmarks and perhaps a miniscule bump in windows boot up/app loading hunting for a kit with better timings might help… Ram speed was more of an Intel issue before it adopted AMD's IMC approach. TBH you won't see a big difference in 90+% of applications. IMO it's not worth what ever fraction of a percent it nets, in terms of ROI spending the extra cash would be better suited elsewhere(GFX card or SSD).
CPU cooler,
Hmm, I do silent but not cheap… it's one of the most underrated components. A good CPU cooler paired with decent internal (case) airflow can make a world of difference in temps, stability, your machines life expectancy and in some cases even power consumption(IE PSUs are ever so slightly more efficient when cooler - or more precisely, they are less efficient as internal temps rise).
Anyway, Coolermaster's Hyper 212+ is relatively cheap and effective. ~$30
PSU,
If you don't have one yet try and find a good 80+ silver or better unit. Let me explain, assuming the specs are accurate and you pick up a PSU capable of 90% efficiency, and say under peak load your rig is consuming 400w(intentionally high number for a single card nonoverclocked rig) then you draw 444W from the outlet/socket. To illustrate my point, pretend the same fictitious rig is paired with a low efficiency (70%) PSU. Your power draw at the outlet would be 571W. I used a higher than likely efficiency for the "better" PSU and somewhat high system draw to just to drive my point. Nonetheless, I can't overstate the importance of the Power supply. Which extends beyond efficiency and includes voltage regulation, ripple and noise(fan and far more rare but prevalent in some low quality units that use crappy caps is resonance aka a whine/squeal sound from an inductor). Long story short never go cheap on the PSU, something that can literally affect all other components…
-EDIT-
If noise is a big deal I would also recommend avoiding sleeve bearing fans and stick to ball bearing… Aside from lasting longer ball bearing fans are preloaded and the weight of the fan blade assembly is evenly distributed through the ball bearings regardless of fan placement/orientation… Sleeve bearing fans, when placed horizontally, the weight of the fan blade assembly is supported at the shaft ends… Thus the lubrication is forced out of the sleeve bearing -> the fan wears/dies quicker and will make more noise as a result.