Also what type of monitor should i get with it (the resolution im unsure) Mouse , keyboard and speakers would help but have the majority. also would i need such as wireless adapters etc.. im really unsure as it's my first time.
The first one should be better in my opinion. The GPU in the Galaxy machine is superior to the one in the Dell. The Dell is also a "reconditioned" machine. Which makes it a no-go just by itself. The Dell has likely an OEM motherboard. The Galaxy has a decent motherboard, and double the amount of memory, and should run BF3 on medium high settings. Keeping in mind, you really need a top end video card or SLI to really crank things up in BF3, it is simply a monster of a game for any machine to run on high settings. But it should be enjoyable to play on the Galaxy machine.
Monitor, I would by at least a 22" 1920x1080 resolution, which is pretty standard for all monitors today. The 1080 res means you can play HD movies or HD content at native resolutions.