It seems that many questions querents seek answers to involve relationships.
A simple spread that I find useful is called "The Relationship Path Spread".
It was designed by two friends, Nina-Lee Braden and Patsy Haggerty.

The cards are dealt in the pattern shown above. Should you need more information on a card, don't be shy about throwing a few more cards in that position for clarification.

Card 1 - How you see the other person
Card 2 - How the other person sees you
Card 3 - How you see the relationship
Card 4 - How the other person sees the relationship
Card 5 - Something about the relationship the querent needs to know
Card 6 - Where the relationship is going

Another Simple Spread:

This is a general purpose spread from the book "Tarot and Individuation", which has 78 spreads in the appendix. It is similar to the Celtic Cross in scope, but is linear, allowing the relationships to be more apparent, and shorter.

Card 1 - Distant past - the basic events and influences that may have created the present outlook and attitude;
Card 2 - Immediate past - recent events that may have had a specific influence and may be on their way out;
Card 3 - Present influences - read with the previous card, it indicates what may modify the present outlook;
Card 4 - Present obstacles, hazards - even if a favorable card, in this position (it) may mean a diversion from the true goal;
Card 5 - Present outlook - usually an extension of cards 3 and 4, it often indicates the way the current situation extends into the future;
Card 6 - Future influences - a summary of all the preceding cards; shows the way they combine to create coming events;
Card 7 - Ultimate result; the culmination brought about by all the preceding suggested interactions between past attitudes and the present.

Another Spread:

This spread is a simplification of a 15 card spread. It is a good general purpose spread which can be applied to a variety of situations or be used as a general "where am I headed" spread.
The spread is laid as follows:

Card 1 - The Significator
Card 2 - Inner Situation
Card 3 - Outer Situation
Card 4 - Direction things will take without outside intervention
Card 5 - Potential alternative action (what you can do to change the course of the situation)
Card 6 - Information which will assist in the decision making process
Card 7 - Forces beyond control that can not be changed

If you have some time to spend, you can expand it to it's full 15 card configuration as follows:

Cards 1, 2 and 3 remain the same,
cards 4, 8 and 12 are read the same way as card 4 was in the 7 card configuration,
cards 5, 9 and 13 the same as 5 etc.
If you use the larger version, remember to look for the relationships between the cards.

Astrological Spread Variation

If you use the astrological spread (12 houses), you can get a much more detailed reading by using the Majors approach I described previously.
Deal the cards for each house, then deal around the circle into each house until you get a Major Arcana. Once a Major appears in a house, stop dealing cards into it.
Keep dealing around the circle until each house ends in a Major Arcana card. You can read the cards in each house as a single group, or you can use each concentric ring of cards to represent a time period; a week, a month, a season etc. This is my favorite large spread which I usually do on New Years Day and my birthday (since my birthday is in June, this works well for a six month interval between major readings).

The Horseshoe Spread

1 - Present position;
2 - Present expectations;
3 - The unexpected;
4 - The immediate future;
5 - Long term future.

This is a short and simple spread that can be modified by adding more cards to each position. This is one of many, many Horseshoe shaped spreads.

The Six Card Cross

Cards 1 and two are laid out like the Celtic Cross, with card 2 crossing card 1.

1 - The role the questioner plays in the current situation;
2 - The true nature of the situation;
3 - What created it;
4 - How it affects the questioner;
5 - Where it can lead;
6 - The key to the situation.

The 5 Pointed Star Prosperity Spread

1 - What the universe can contribute to the querent's needs;
2 - What can help the questioner be relaxed and at ease;
3 - What will bring prosperity and contentment;
4 - What will counterbalance the questioner's negative feelings;
5 - What can provide rewards, positive feedback, reinforcement;
6 - What prosperity could mean to the questioner.

See also: The Celtic Cross