Building Minecraft Servers

Ok, im tired of searching the web for a strait up answer for minecraft server hardware, all the forums that i check no one gives an answer other than "What speed is your upload if you are under xMb/sec then you should forget about hosting servers."
I dont plan on hosting a server for 50 plus people at once, its just for me a few family members and a couple of freinds, i checked my upload speed and its more than addiquit for my group, so this is what im wondering. What "hardware" do i need to run a minecraft server, with 80 plus mods, and have little to no lag?
mind you this pc is only for a minecraft server. nothing else. ive made up a list of parts that i just brain stormed together

any advice and help is greatly appreciated. also sorry bout the grammer, i always hated english and i barely passed it

Case: Bitfenix Prodigy
CPU: Intel Core i7-3770K stock cooler
Mobo: Asus P8Z77-I Deluxe/WD
Memory: Corsair Vengence 16GB (2x8GB )
Storage: Corsair Neutron GTX 120 GB (OS, Minecraft Server)
Western Digital Red 1 TB(storage just in case)
PSU: ? enough to power and handle future drives and is semi modular, also if i ever convert it to a small gaming rig and add a graphic card thinking HX650?

and i have no clue what os to run ive seen alot of windows 7 and linux based servers, but ive never used linux and wouldnt know where to start

It wont use more than a single core for MC and a core for the databases and stuff usualy so the fastest dual core you can get or like a 2500k/3570k will be more than enough, for better results overclock it , also 8gb ram will be more than enough tbh, i used to have 3 servers (public freebuild, smp + a plugin testing/mess about server) and a classic server running on an amd hexcore with 16 gb ram and the most usage i saw was about 65% cpu + 9gb ram used (2.3gb was tied up in firefox with a million plugin pages open) and alot of that was having 3x of every plugin running. OS wise Win7 will be fine, linux saves you a little ram but its a major ball ache to set up.

Ignoring the maybe it turning into a gaming machine later id personaly just go:

Fastest 1155 dualcore you can get for a reasonable price.
8gb ram
Case you said
any old ITX board
430w builder series from corsair
A reasonably fast mechanical HDD like a spinpoint F3 or what ever is fine.

On the maybe future gaming machine side id go

2500k/3570k (overclock it a little with a 3rd party cooler)
8gb ram
Board you said
Case you said
530w bequiet L8-cm
Same as above, reasonably fast mechanical drive like a spinpoint F3.

The ssd is only realy noticed when you have a bunch of people using world edit often or teleporting all over and this can be nigated by putting the map on a ram drive anyways so if you will be doing that uping to 16gb ram may be an idea but isnt essential.

Just like what he said^ all you need is a basic dual core and good amount of ram.
This is about the closest you can get to telling you what you need for your server. http://canihostaminecraftserver.com/

wow, thnx for the quick reply ive been searching everywhere for weeks and finally i gave up and just asked some people that i knew would know the answer thumbs up guys, now all i need is get my buddies to pitch in for the build

80+ mods might be a little tricky though, bare in mind smp is nowhere near as stable mod wise then client, so the choice of mods will be quiet important.

spec wise, you really dont need even an i7, get a 64bit cpu so it can actually use that ram on ram you'll probably want dedicated 2gb-6gb depending on whats going on on the server, if you have nukes going off every minute you'll need that ram, but if you will be playing survival then 1gb should be enough.

most important when running server is the up and dl speeds, that will pretty much determine the amount of players you can have at one time.