No there is no need to fill out the Dell form on eBay, you just simply buy it. You can buy the DVDs from eBay even if you don't own a Dell system (theres just little point). You can only use it with a system that has a Dell Windows 7 Professional COA or a Dell system that came with Windows 8 Professional and as a Windows 8 Professional product key in the BIOS.

You can just purchase the DVD on eBay I bought one the other day from ebay.co.uk

The DVD I bought is good as the .iso image of it is identical in size to the Windows 7 Home Premium with Service Pack 1 DVD I got with one of the Optiplex 790s we have in the lab.

"The request form mentioned should get you the reinstallation DVD on eBay hopefully for free or a low price" Phillip, just to clarify, those OEM 7 Pro discs on Ebay don't require me to fill out that Dell form? Correct?

It is indeed free of charge to use the Dell form.  eBay is not free :)  Phillip is from the UK - it is NOT free in the rest of the world, so they are fighting a harder battle to get this media ... for now.

With similar experiences as yourself, I'm also a little fed up with Dell.

I ABSOLUTELY have my issues with Dell, but to be fair, this problem/policy of obtaining media is NOT unique to Dell.  This is a problem plagueing ALL customers of large OEM's.  ZDNet's Ed Bott recently did a story on obtaining installation media from OEM's, wherein he said that Dell was by far the best of the main OEM's for obtaining media.  This is good, but, in my opinion, not good enough ... there needs to be a more streamlined way to get this media - for everyone - starting with including the media with systems in the first place.  Honestly, OEM's are not 100% to blame either ... from my understanding, this whole "media reduction initiative" is spearheaded by Microsoft.

"they seem to push those Data-Restore-Back-Up discs"

Yes, they do.  Microsoft has "partnered" with OEM's to reduce the amount of media being distributed with PC's by encouraging OEM's to implement recovery partitions, from which a system can be returned to the factory image or create recovery disks of that image.

The page to request a media is called Request Backup Discs, and proceeds to explain the options you have as shipped from Dell (DataSafe), by explaining DataSafe and how it works as an alternative to installing from the installation media.  However, at the end, it says, "To proceed with requesting these backup discs", then fill out and submit the form.  This media DOES NOT have ANY OEM or proprietary drivers on it.  This media DOES NOT have ANY software loaded on it that is not on a Microsoft Retail (or generic OEM) installation disc.  And this media is EXACTLY the same as the Dell installation discs you would buy on eBay:

http://www.ebay.com/itm/DELL-WINDOWS-7-PROFESSIONAL-32-BIT-SP1-REINSTALLATION-DISC-DVD-/200867936819?pt=US_Other_Software&hash=item2ec4a97a33

The ONLY differences between the "backup disc" from Dell and a Retail disc from Microsoft is:

- Branding.  OEM's load their own default backgrounds/wallpapers, login screens, and user account tiles, and place their logo in the Windows Edition section of System Properties.  Anyone can change/add these to their own install, and it is designed for OEM's (big, like Dell, and small) to be able to brand their media (mine is currently Ironman branded :)).

- Activation.  OEM discs look for a BIOS string which identifies the system to the Windows installer.  Some OEM's use this to block installation altogether - for example, an HP Windows DVD will not install on a Dell, Acer, etc., nor will it install on a machine significantly different from the one it shipped with.  Dell, from what I hear, will install on any system, BUT automatic/SLP/OEM activation will NOT occur unless the BIOS string matches what the installer has been told to accept.  In this case, manual activation would be required by typing in the Product Key, and depending on the situation, phone activation may be required.

Other than these, everything is the same as a Retail disc - same built-in drivers, same native software (including DVD codecs), etc.

So, you could purchase a Dell-branded installation DVD on eBay (which I've seen sell for between $5-30) or you could fill out the form to get the media for free from Dell (if you were not the original purchaser, you might need to do an Ownership Transfer first).

Again, you could certainly put down $100 and buy your own, but it's not necessary, unless you like the idea of legally being able to migrate that installation to another machine (physical or virtual).

Technically speaking, the generic/Microsoft OEM version you linked to is licensed to be installed on a new PC to be sold to another party.  Generic OEM software (also called "System Builder" software) is NOT intended for people building their own PC (I realize you didn't "build" this one, but the concept is the same in the license), but for those building a PC for resale.  You would not be the only person to do it (in fact, you might be in the minority if you decided to abide by the technicalities of the license :)) ... I just wanted to point that out to you.  If you were to ask Microsoft and abide by their licensing, you would need to purchase the "Retail" edition of Windows 7.

One other alternative is to obtain "retail" media (can be downloaded officially from below) and install Retail media, then use phone activation to activate using your Product Key on the sticker (activate with Microsoft, not Dell).

http://www.mydigitallife.info/download-windows-7-iso-official-32-bit-and-64-bit-direct-download-links/