Are there any books/articles/websites/email programs that can help provide a daily Hizuk?
By Hizuk, I mean something gives one more of a mood to be Oved Hashem.
What can be more mechazek than a daf of Gemara? There's a daily Gemara program which learns one daf per day called Daf Yomi. Shiurim are easily available on websites such as DailyGemara.com and YUTorah. Furthermore, since the program is widespread throughout Jewish communities across the globe, you can likely find a Daf Yomi class in your local synagogue or bet midrash.
I highly recommend basically any Breslover seforim. I'm currently enjoying Rabbi Yaakov Meir Shechter's - A Scent of Eden. This sefer is both an educational manual in improving avodas Hashem as well as full of powerful and inspiring Torah to be m'chazek the learned and unlearned alike.
Charlie Harary, a noted speaker on inspirational Jewish topics, said in a talk/Q&A (2/29/2012) at Yeshiva University (in the presence of YU Rosh Yeshivah Rabbi Yaakov Neuburger) that there are three books that give him chizzuk whenever he learns them. They are:
1: Nesivos Shalom,
2: Michtav Me'Eliyahu (Rabbi Dessler's Strive for Truth),
3: Sifsei Chaim.
Also, I once heard that the two favorite musar sefarim of Rabbi Avigdor Miller ztz"l were:
4: Mesillas Yesharim
5: Chovos HaLevavos.
Rav Miller was said to have learned these two seforim for hours on end when taking a break from learning Gemara during the time he spent learning in Slabodka.