My Retirement Game Plan

I don't have an actual number in mind. Because I'm very young (turning the big 2-5 this year!), I feel like there are so many variables that it is really difficult to get a good feel for what amount of cash I'll need and at what age.
What I do know, is that I want the possibility for the age number to be low! Unless the rules change, I'll be able to withdrawl from tax-sheltered accounts like my 401(k) at 59 and 1/2- but what if I want to go out at 50 or 55 instead?
That's why it is important for me to utilize multiple retirement vehicles. Right now I'm using:

1) My 401(k) with match through my employer- I like this because my employer matches it with some free money, and it keeps California's paws off some of mine- at least for now, and I can't see myself retiring in one of the highest taxed states.

2) My Roth IRA- I like this because it lets me grow earnings tax-free, and with our budget being 48% loaned this year (which makes me sick) federal taxes will certainly be going UP in the future. Also, my investment choices are basically infinate compared with my 401(k). I could use some on a home down payment eventually, but I'd rather let it continnue to grow if I can.

3) My Mutual Fund account- I like this because I could consolidate to cash if I need/want to. This lets me not only keep it as my "before 59.5 nestegg", but I have the option of using it for a down payment on a home, or liquifying some to live on during an extended job loss or something like that. It also allows me to save additional cash in years I max out the other two options.

4) Social Security- HA. Ha. ha. Government's cruel joke for us younger folk. Not a snowball's chance in you-know-where this program will pay me anything in 40+ years, but I'm stuck paying it anyways. Imagine how much that sum could be if my SS payments were invested modestly and the program worked as it was originally intended to... ah, sweet, parallel universe.

I think with very few (if any) exceptions, everyone should max out their employer match first if they have one in their 401(k). From there, it really depends on your situtation and what kind of taxes you pay now vs. what you expect to in the future. Of course, I'm just a regular gal and no expert, so don't go taking my words as gospel.

What about you guys? Thoughts?