Don't get crazy with that, you need to know what it is that you're unchecking.
Go line by line and do a search on google. There are a lot of sites that will tell you what you're looking at and if you need it in there at startup. A lot of services should be there, but you can't always tell from what you're looking at. Your antivirus suite may have a tool to help with this, I know TrendMicro does.
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Xbox 360 & PC
•AMD Athlon 64 X2 DC 6000 •3GB PC2 5300 DDR2
•BFG GeForce GTS 250 OC, 1024MB GDDR3 •Creative SB X-Fi Fatal1ty Pro / Logitech Z-5500
•Win 7 RC 7100 / Vista Home Prem / XP Pro (who knows, varies with the wind)