Financial / 401k advice for a 23-year-old engineer.

Financial / 401k advice for a 23-year-old engineer. Considering the state of the economy and the price of oil, what should I do with my stocks. Also, I have the option for a 401k but I have no idea what type of 401k to choose. I have around 30k in McDonalds stock that is up 80% from when it was bought for me when I was a kid. Should I hold onto it and weather the storm? I keep reading rumblings of a recession and stock market crash but is that just a scare tactic? I don't want to get kicked back down to a 30% gain on that stock when it's been doing so well up until right now. It has defintely been a long-haul stock but I'm afraid I'm going to lose all that I've built up over the last 23 years. Also, I've had the opportunity to enroll in a 401k from my company for the last 6 months. I haven't done it yet mostly because I have no idea what to fill out on the form. I have the following options. Any recommendations? I believe my company matches up to 15%. Should I go with option 1 or option 2? 1. I elect to contribute ____% or ____$ (per pay period) of my compensation as before-tax contributions to the 401(k) Plan until such time as I revoke or amend my election. 2. I elect to contribute ____% or ____$ (per pay period) of my compensation after-tax as a designated Roth contribution to the 401(k) Plan until such time as I revoke or amend my election. Note: The total of your before-tax and Roth deferrals cannot exceed 100% or $15,500.00. Your before-tax and Roth deferrals must be specified consistently (both as a percent or both as a dollar amount). If I am 50 years of age or older and I am eligible for a catch-up contribution, I understand I may exceed this total. I also have all of these to pick from. No idea what to go with here. Considering the economy and what I hear, I'd probably rather take a semi-conservative approach. Maxim Aggressive Profile II Maxim Moderate Profile II Maxim Conservative Profile II American Funds EuroPacific Growth R3 Oakmark International II Oppenheimer Global A First American Small Cap Select A MainStay Small Cap Opportunity A Maxim Index 600 RidgeWorth Small Cap Growth Fund I Lord Abbett Mid-Cap Value A Maxim Ariel Small-Cap Value Fidelity Advisor Mid Cap T Fidelity Advisor Leveraged Co Stk - T American Funds Growth Fund of Amer R3 Davis NY Venture R Marsico Focus Maxim S & P 500 Index Maxim T. Rowe Price Equity Income Oppenheimer Capital Appreciation A RiverSource Diversified Equity Income R3 Van Kampen Comstock - R Maxim Bond Index Maxim Loomis Sayles Bond Portfolio Maxim US Government Securities Fund PIMCO Total Return Admin Guaranteed Certificate Fund 36 Month Guaranteed Certificate Fund 60 Month Guaranteed Certificate Fund 84 Month Maxim Money Market Any help would be fantastic.