I'm planning on making a HTPC on this income tax. I have the build pretty much ready as it will use my old dual core celeron sandy bridge processor and micro atx mobo and some of my current builds parts when I upgrade it (4gb ddr3, 550 W psu, Radeon 6850 1gb, 250gb WD HDD).

Anyways I'm wondering if anyone would know what would be a good... Idk, I guess operating system for it? I was planning on using Windows 7 but I've also heard that there are programs designed specifically for HTPC. I'm not really planning on ripping movies or music or anything but am more likely going to use it for Netflix, Hulu +, and some web surfing.

Linux is free. There are distros that use a Windows-like environment, so that sounds like a good choice. If the HTPC has an optical drive(I'll assume it does), just put the distro of your choice onto a disc and install it from that. You'll need to make sure to look into how the clients you'll use will work with Linux or be installed onto Linux, but if you are out of activations for any old Windows discs, then Linux seems to be a good, very cost effective alternative. Windows 7 does have a mode that makes it seem more like a media center, so if you have any spare activations on a Windows 7 disc, just use Windows 7 due to the larger amount of support Windows has. Go into Gadgets and you'll find one that has the word Media in its name if using Windows 7.

First choice would be the case. They have cases that are about the size of an audio component and look at home in the stack of your other stuff. These cases tend to be smaller, although if you have a case already that you like then use that.

The other consideration is noise. You want this thing to be as quiet as possible, so larger slower turning fans, perhaps fanless heatsinks (you can even underclock your CPU for this type of use). There are video cards that have no fans on them, and some that have quieter fans.

Windows 7 is a decent Media Center by itself, so you can use that.

Netflix now supports Linux, so you definitely can go that route and save the money from there to buy more HDD space or a nice case. If it's not going to do any gaming (or just minor gaming) that can be a good option. XBMC (now known as Kodi, but that's a horrible name IMO) is a great frontend for a HTPC and integrastes both hulu plus and netflix.

If you're planning on recording shows, though, I may actually suggest Windows. While there is MythTV, it's an involved setup and Windows Media Center is a lot simpler.

Are you looking to record cable/satellite shows then it is important in getting the right tuner card especially for HD. The problem might be with you cable/satellite provider might not provide the correct channel guide and listings so you might lose out on proper programming to record when you want to.

Myth TV (Linux package) designed for this type of feature is not too difficult to install but it is important to look at the hardware that works with it as well see if any reported issues if you are looking to record shows from your cable/satellite provider. Some providers do have a listing guide that Myth can use to make it easier to interface to schedule programming but some providers make it difficult since they only want you to use their DVR

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Here is a link for some guidelines in setting up a HTPC.

http://mymediaexperience.com/first-htpc-tips/

From what I've seen, many of these HTPC cases that have very small builds are ITX ones. I don't know if any micro ATX cases can be found with these kinds of looks.

Noctua has some low profile coolers for builds like this. I checked to see exactly what your CPU probably is and if it's the Celeron G540, then that means you are using an 1155 socket board. Most likely, anyways. Measure the case if you've already got it and look at the size of any coolers you'd feel were good. Noctua's U9B SE2(this isn't exactly low profile) is a fairly small one if you have a case that can hold somewhat standard sized air coolers. It also works with the 1155 socket. If the case is smaller, look deeper into Noctua's catalog. If nothing strikes you as good, then looking into other brands is the next choice. Noctua is my personal favorite company to get silent stuff from, but if it isn't one you like, there's plenty of other options.