Sorry, I meant 802.3x, I always get those two confused.
You always want to autoneg, in addition to pause negotiation (and in the case of 1000BASE-T master/slave negotiation), if you force the speed and that stops the PHY from responding to auto neg and the other side autonegs then the other side believes it is talking to 10Mb/s half duplex ancient stuff. The PHY will normally catch the speed mismatch and give you connectivity, but there is no way to catch the duplex mismatch, leading to a ton of spurious collisions and really terrible performance. Most stuff these days when you force the speed is still doing autoneg just with a limited set of speed/duplex options to avoid exactly this scenario.
Gigabit Ethernet in the home is 1000Base-T and only requires Cat-5 http://en.wikipedia.org/wiki/1000BASE-T#1000BASE-T
You may get longer runs and better noise immunity on Cat-5e and Cat-6, plus Cat-6 is 10GigE capable, but Cat-5 is sufficient. The signal bandwidth on the cable is the same as 100Base-Tx, it just uses all the pairs bidirectional and with better encoding to get the improved speeds.
Gigabit switches are cheap if you go for the plain unmanaged ones. I've got 3 of the DGS-1008 from D-Link which are currently $50 Canadian http://www.ncix.com/detail/d-link-dgs-1 ... Mgod71oAVQ
there are similar from all the other switch manufacturers.
Like a great man
once told me: "Anything auto, you oughtta not use it".
With a few exceptions, that still holds true for me.
I'm definitely mistaken about Cat5 not running GigE. My bad! Guess I'm just too used to having to run Cat6 to GigE and 10GigE SFPs.
I will disagree about unmanaged switches, though. Maybe I'm just jaded from seeing those things FUBAR networks in production environments, but that's me. I love having control over the switches, and being able to segment out traffic per-VLAN, idiot-proof trunking, Port Security, QoS enforcement, etc...
And I'm kinda ashamed to admit it, but I've got a knee-jerk reaction to all things D-Link. A former CTO was getting kickba...er, "revenue share" from D-Link to deploy their unmanaged switches all over the place. They caused nothing but headaches, when a managed switch (HP ProCurve, Cisco, etc...) would've resolved all the problems we encountered. I need to work on that.