what are the different USB sheild options for an UNO

I am wondering what the difference is between a USB host shield like you would find on SparkFun or something like a USB convert like the following.

PL2303HX USB To TTL Auto Converter Adapter controller Module for arduino

I am wanting to use this for a bluetooth dongle would either work? I like the smaller one because it isn't a shield and I can move it around - it doesn't need to be attached to the Arduino like the shield.

Thanks

There are many USB/Serial adapters like the FTDI Basic, which uses an FTDI FT232 chip, you can find them with FT232RL package with leads, FT232RH with no leads, and various USB connectors (large USB-B, smaller USB-B Mini, and really small USB-B Micro). You can find them with PL2303 chip instead, with CP2102 chip, WD403 (I think that's the number), showing up on numerous clones, and with Atmega8U2 at the Arduino store. All three of those need an external crystal. The FT232 has in internal oscillator and needs no crystal. FTDI had their driver not working with counterfeit FT232 chips for a while. PL2303 I thought had driver troubles (or no driver available) with Win7 or Win8.1. You should check on that. I've only used FTDI based boards myself with Win7 Pro and IDE 1.0.6 as one reference point. I did try some CP2102 modules when I was running WinVista a year+ ago, modified with a trace cut and jumper add to bring the DTR signal out to the IO pin (vs the chip's Reset signal). Those worked fine.

thanks - I am not 100% sure why a windows driver would matter?

I want to connect the shield / adapter to my arduino and stick my bluetooth adapter into it so I can connect a wii mote, that is my goal however I would like to use one of the smaller USB modules like this one on ebay - “6Pin USB 2.0 to TTL UART Module Serial Converter CP2102 STC Replace Ft232 Module” to plug my bluetooth dongle into so I can run some wires and mount it away from the Arduio which will be buried inside of the car…

I would presume so long as I can get it working on the Arduino I don’t need to have a windows driver.