I completely agree about Geometry Wars 2 - I don't like shooters but it got me really interested in playing the Xbox (period), especially with all the diff modes of play.
There are quite a number of interesting XBLA games if you're fine with download items, such as
Bastion, Pinball FX 2, and the hard copy of the Triple Pack with Limbo/Trials HD/'Splosion Man has gone on sale a couple of times which is an excellent deal for the 3.
As for the Live sub, I wonder if they just said "lifetime sub" just for the Silver, as that is free. If you need a gold sub, I still have a few 12 month gold cards available that I bought for cheap in case you want to purchase one from me
Here's a list of the differences that I sent to a roommate back about 6 months ago paraphrasing what's on the xbox site:
free membership - SILVER:
Preview games with free demos
Watch HD movies and TV from Zune (if you have a Zune membership)
Download new games and game add-ons (sold separately)
Create and customize your Avatar
Industry-leading, built-in Family Settings
Chat and text with Friends on Xbox LIVE
paid membership - GOLD:
Everything you get with SILVER
Download exclusive game demos that might not be available to SILVER members
Play games online with friends
Instantly watch HD movies from Netflix (if you have a Netflix membership)
Instantly watch last night's TV today with Hulu Plus (if you have a Hulu Plus membership)
Live sports from ESPN on Xbox LIVE
Video Kinectâ„¢, Facebook and Twitter on your TV
Personalized music from Zune* and Last.fm (if you have a Zune membership)
Gold subscriber-only sales