In the market for a new desktop

[GenMarshall]

Now comes my next question, which video card Mfg should I chose that is more reliable, especially in regards to cooling? NVIDIA (GeForce) or ATI (Radeon)

 

[innonimatu]

I have set aside a budget of US$1,500 (I plan to buy the monitor, speaker system, and a SD card reader separately at BestBuy) and going to go with Dell since my employer offers a discount to their employees if they purchase a Dell.

Without monitor? Half that budged should suffice. Save the other half for when you'll have to buy a replacement in a couple of years, because quality of PC components has really sunk. Better to accept it, buy cheap and replace the broken . .. .. .. . that spend a log and have fail the same way!

The system that I intend to have would be for gaming (moderately, sufficient enough to run Half Life 2 on high), surfing the internet, and image editing and digital photography. Along with the ability to upgrade and/or replace hardware.

Most hardware nowadays is integrated into the motherboard (nic, sound, etc.). But you can at least make sure that the case is large and the board is a normal ATX one and not one of those micro-ATX cheaper things which have flooded the market. Most cases on sale are also very thin and prone to irritating vibrations. A pre-assembled desktop from a big brand will probably not have those problems.

What should I be looking for in terms of RAM? I don't want to spend too much money. Plus I am not that comfortable jumping to a 64bit OS since I am unsure about it's compadibility with 32bit programs and games.

Windows 64bits (both vista and XP) is compatible with 32bits. Linux is not, by default, but that's because open-source software can simply be recompiled and distributed for 64bits. With windows you get a mix of 32 and 64bits applications, but it works, even if it's not elegant.

The 3GB of memory typically usable by 32bit systems would be enough (it is for HL2 and CIV2, for example). Frankly I cannot see the possible use of over 4GB of memory in typical desktops for the next 2-3 years. But perhaps some image editing programs can make good use of it while working on large sets of big photos. You can always add more later, just make sure to leave free slots. And don't pay for overpriced "performance" memory, you won't notice the difference.

On top of that, what is the trade off between having a Dual Core processor that would give me 3GHz or a Quad Core processor that would give me 2.4GHz?

The faster dual core will be faster on the vast majority of applications, but as apps usually don't require much processor power you won't feel the difference here either.
Most recent apps that do require lots of processor power (games, simulation, rendering, etc) have already been updated to take some advantage of more processor cores. So I'd suggest the quad core, but it really depends on the use it'll have. Civ4 doesn't really benefit

 

[Mulholland]

Now comes my next question, which video card Mfg should I chose that is more reliable, especially in regards to cooling? NVIDIA (GeForce) or ATI (Radeon)

They're both very good. As long as you get a card without any manufacturing defects. I believe Radeon has the priceerformance edge right now with the 4850. But if you get a deal on a 9800 gtx you will be very pleased as well.

 

[Genocidicbunny]

At very high resolutions and with DX10, nothing beats the GTX 280 in price ( the HD4870X2 does beat it in performance, but its around 100$ more expensive). I personally bought a GTX 260 Core 216 which cost me around 210$, and I have a feeling its gonna get very good performance for the money ( Havent assembled the pc yet, PSU hasnt arrived). But really, the mid-upper range cards from both nVidia and AMD are very good. You have the HD 4850 for AMD and the GTX 260 Core 216 for nVidia. As to which manufacturer specifically, I've had good relations with both EVGA and Sapphire for nVidia and AMD respectively.