Exxon stock (NYSE: XOM) is one of the most sought after long terms investments. The nearly $500 billion company, is a virtual cash cow. Many see solid returns from Exxon as inevitable as taxes and death. With oil hovering around $100 per barrel and Exxon up over 136% (ex-dividend), is 2008 the right time to make this entry long term?

The reality is that for the past five years Exxon has demolished the returns of the S&P 500. This is an enticing tidbit for many prospective investors. If you look a little deeper into its peer group, however, you may notice that Exxon has some interesting weaknesses. For example, its net margin, around 10%, but foreign companies PetroChina (NYSE: PTR), Petroleo Brasileiro (NYSE: PBR), Eni S.P.A. (NYSE: E), and Petro-Canada (NYSE: PCZ) all have better net margins, ranging from 11.1%-19.9%. Also, with regards to its price-to-earnings, Exxon stock is currently sitting at 11.8x earnings. All but one of the largest ten companies in its industry offer more value on a price-to-earnings scale. Even relative to its own seven year price-to-earnings scale, Exxon is falls right in the middle of its range (8.25-14.01) of its 3 year P/E history.

Many investors appreciate the premium that Exxon trades at because of its stable growth and solid management. Its long term growth rate is projected at 5.8% this year compared to an average of 1.9% among integrated oil and gas companies and 2.4% for the Energy sector as a whole. Short term, things look less rosy for Exxon with its estimated growth at 11.2%, compared with 17.5% for the integrated companies and 20.2% for the Energy sector as a whole.

Analysts tend to be overweight Exxon in the recommendations. Currently, 4 have the company as buy, 6 as overweight, and 8 as hold. Weighing all of these factors and the potential for recession and tighter refining margins, 2008 may not be the best entry point for investors looking at Exxon Mobil stock. However, given its long term performance, this may all wash out in the end. If you do jump in this year, I recommend automatically reinvesting your dividends back into the company.