I am a squirrel when it comes to spend. This also applies to my hobbies. Although I spend roughly one third of my time on my PC, I think 10 times before buying any upgrade, hardware or software. On the other side I also averse to free softwares for the fear of getting my fare share of virus and spam ware.  My elaboration of top 10 freeware starts with the premise that I am using a genuine Windows XP version of Operating system and hence my evaluation is limited to the usage in windows O/S only with the exception of Linux as an OS.

1. Office Suite : Open Office – I have an option of Star Office to rate as number one in place of  Open Office for the sheer reason of its bundle with Java and more templates. However a free distribution or not even registering with the additional feature of saving your work as pdf made my choice clear. Since I wanted to include only one software in each category Open Office became the choice for the other reason that it has already clocked more than 60 million downloads. Oo v2.2 offers a bunch of cosmetic changes to the interface. Open Office has enough to save 11.5K for me if I am not taking the market leader MS Office. Choice of having a genuine usage than using a pirated MS without sacrificing any substantial stuff and the amount saved made OO the number One in my ranking.
2. Operating System: Linux – As I mentioned earlier, Linux is the only exception in my ranking. I am a clear admirer of Linux and use it too as a dual boot, though my normal routine usage is on MS Windows XP. Linux, to me is a movement and a revolution to challenge the dominance of MS XP. Paying INR 8000 for WinXP was a compulsion. It ranked 2 because it is free, limited Virus target, future and the source code. I shall be thankful if any MSian suggests the best things on usage of Linux (I use Ubuntu Linux).
3. Multimedia: VLC Media Player – All my multimedia installations are crying foul or feeling shy after VLC media player took charge of the PC entertainment responsibility. This cross platform media player asked me to say goodbye to others by assuring me to play almost any type of media file. I too responded with a high ranking of No.3.
4. Browser: Internet Explorer 7  - There was a fierce competition between Opera and Mozilla firefox to take the slot for their flexibility, size and features. I went for a weightage system for all the features (ease of usage, size, goodies, security, speed) and surprisingly IE7 came as the winner in all categories except the security and possibly on speed to some extent. Due to its popularity IE is the target of virus and malwares. At the time of installation it checks if the OS is genuine (runs only XP onwards). I  had to accept it as my browser and using it.
5. Antivirus: AVG Free Edition – Antivirus is a must for every PC. Its usage is not only to safeguard your data but also to protect PC performance (speed). After the expiry of my Mcafee trial period I had installed Avast Antivirus after doing some web exploration. There were many problems and incompatibility issues with it. My PC uses external hard drive, ADSL modem, Netgear router, Pixelview TV tuner along side the essentials like ext CD ROM, Printer … My experiment with AVG free edition became a success story and saved quite a buck. It updates automatically and cleans too.
6. Digital Image Viewer : Irfanview – Irfanview and XNView are two best free digital image viewers and both are similar in many ways. Most popular among them is Irfanview though XNview scored well in the multiple image criteria. Both are capable of viewing and editing almost all graphic files. Irfanview entered the choice arena on popularity. It’s quite capable at processing images, adjust brightness, color filters,effects, cropping, re-sizing, converting format in single frame or as a batch.
7. PDF Utility : Primo PDF – At the point of uploading this view on freewares, there are many utilities to take care of creating and editing of Portable documents. However I started using Do PDF and Primo PDF (more frequently) long back and I am fairly satisfied with the way it works. The most satisfying feature in this is it works as a virtual printer and I convert my web tickets etc to a pdf file simply by giving a print command.
8. Bittorrent Client : uTorrent – uTorrent and Azureus are the most used bittorrent clients world over. Both are free good and capable. Only difference is the user preference. I gave up using bit-lord long back since it was not acceptable to many P2P sites. I am very satisfied with uTorrent and never felt to use azureus. However most of my friends use Azureus and the feedback is astounding.
9. Mail Client – Mozilla Thunderbird – Wondering why this capable utility is at number 9? It is certainly very good utility. However the ranking is on the basis of my usage and the other 8 scoring better on different parameters. Its extensions like webmail and google indexation makes it to the top.
10. Compression Utility: 7Zip – Winzips limited features and message display prompted me to look for an alternative and 7zip fitted the bill. The compression speed and compression percentage secured it a place in top ten freewares. You may try it.

My friends suggested many other alternatives. Since I have not used those and never felt also. The ranking and choice carries subjectivity and confined only to my limited awareness of the web.   
You may add to my views………………