I have jotted down a list of five best Desktop Computers for the usage you have particularly mentioned. They include a wide range of features and price, as you haven't specified anything in particular.
1. HP AIO 20-C102IL 19.5-Inch Screen All-In-One Desktop
This 19.5 inches All-in-One Desktop has a diagonal widescreen with full high-definition and VA WLED-backlit display. It has an Intel Celeron J3060 (Braswell-D) Processor, with Molokai-U Motherboard. The Desktop has 4 GB DDR3L-1600 RAM, 1 TB SATA 7200 rpm ROM. Running on DOS 2.0, it comes with Integrated Intel HD Graphics and Integrated speakers. Other features include
Integrated Bluetooth of 4.0 version, Wireless LAN 802.11b/g/n featuring 2.4 GHz 1x1 technology and Ultra Slim Tray with Super Multi DVD Burner drive.
2. Asus ET2231IUK-BC018X 21.5-inch All-in-One Desktop
This computer from Assus has a 1.7GHz Intel Core i3-4005U processor with 4GB DDR3 RAM and 1TB 7200rpm Serial ATA hard drive. This device has got a big 21.5-inch screen supported with Intel HD 4000 Graphics. The desktop works on Windows 10 operating system.
3.Dell 3 Years Warranty All-in-One Computer 3030
This All-In-One Desktop from Dell has a Intel Core i3 i3-4150 3.50 Ghz Processor with a RAM of 4 GB whose 2nd Slot is left empty to support upto 16GB of space. The salient features include HDD of 500 GB and the OS on which is works is Ubantu. The device brings along with it a Wired Keyboard with Mouse. The display Size is 19.5 inches. The standard features are in place, Wi-Fi with Bluetooth, DVD Writer and above all it comees with a 3 Years Onsite Warranty from Dell.
4. Dell Inspiron 3647 19.5-inch Desktop PC
This computer is powered by a 3.1GHz Intel Core i3 processor with 4GB DDR3 and 500GB 7200 rpm Serial ATA hard drive. It has 19.5-inch screen with Intel Graphics. The device on runs on Linux and Ubuntu operating system.
5. HP 20-c103in All-In-One Desktop
This All-In-One Desktop Computer works on Intel Celeron Processor of 2.48 GHz. The RAM Size is 4 GB with DDR3 SDRAM Memory with a Hard Drive Size of 500 GB and an eSATA Hard Drive Interface. The Desktop runs on Windows 10 Home 64Bit Platform and Intel HD Graphics.