Help buying laptop hp pavillion dvt4 or dv6t select

Hello,

LOOKING TO BUY,PLEASE HELP,…
1.HP Pavilion dv4t-5100 Entertainment Notebook PC
Genuine Windows 7 Home Premium 64-bit
3rd generation Intel(R) Core(TM) i5-3210M (2.5 GHz, 3MB L3 Cache)
==Could upgrade to ==3rd generation Intel(R) Core(TM) i7-3612QM (2.1 GHz, 6MB L3 Cache
Intel(R) HD Graphics
8GB DDR3 System Memory (2 Dimm)
750GB 7200RPM Hard Drive
===Another option===500G 7200rpm
NO mSSD Hard Drive Acceleration Cache
No additional security software
6 Cell Lithium Ion Battery
14.0" diagonal High Definition HP BrightView LED Display (1366 x 768) SVA
Microsoft(R) Office Starter: reduced-functionality Word/Excel(R) only, No PowerPoint(R)/Outlook(R)
SuperMulti 8X DVD+/-R/RW with Double Layer Support
Webcam with Integrated Digital Microphone
802.11b/g/n WLAN
Standard Keyboard Black
HP Home & Home Office Store in-box envelope
++++++++++++++++++++++++++++++++++
2.HP Pavilion dv6t-7000 Select Edition Entertainment Notebook PC
Windows 7 Home Premium 64-bit
3rd generation Intel(R) Core(TM) i5-3320M (2.4 GHz, 3MB L3 Cache)
Intel(R) HD Graphics
8GB DDR3 System Memory (2 Dimm)
Microsoft(R) Office Starter: reduced-functionality Word/Excel(R) only, No PowerPoint(R)/Outlook(R)
750GB 7200 rpm Hybrid Hard Drive with HP ProtectSmart Hard Drive Protection
NO mSSD Hard Drive Acceleration Cache
No additional security software
6 Cell Lithium Ion Battery - Up to 6.0 hours of battery life +++
15.6-inch diagonal HD BrightView LED-backlit Display (1366x768)
SuperMulti 8X DVD+/-R/RW with Double Layer Support
HP TrueVision HD Webcam
802.11b/g/n WLAN
Standard Keyboard with numeric keypad
HP Home & Home Office Store in-box envelope

=Trying to keep it $800 but prefer 14”
=If I am using 1T of external hard drive= how much hard drive memory I need,500 or 750???
=Do I need 8G or 6G??
=Much difference between 7,200rpm and 5,400
any problems using stereo mix??
Please suggestion- I am no GAMER,…just looking for fast ,long lasting notebook,…
thx