In my opinion, the most important product to invest is the moisturizer. Personally (having combination skin) I prefer cream instead of gel, once it makes the skin more comfortable and the hydration lasts longer.
At the moment I'm using Chanel's HYDRAMAX+ACTIVE cream - excellent hydration, super comfortable texture and delicious smell. It doesn't have SPF so it is very light and I use it as a day and night cream.
Chanel's HYDRAMAX+ACTIVE cream, for more information click here.
Another great option is Guerlain's Super Aqua-Day Comfort cream. I used it for the last 3 years but I found out that Chanel's HYDRAMAX+ACTIVE supplies my skin's hydration needs better (my skin is really picky). It has SPF 10 which is not much but it's better than zero (I use SPF 30 all year long so I still had to apply it after the moisturize). The texture and smell are also great.
Guerlain's Super Aqua-Day Comfort day cream, for more information click here.
A great tip to save cream and make the application easier is to use a generous amount of alcohol-free tonic before the cream (more on that topic later).