Hi - not sure if this is the place to post this type of thing as it is not really a question, but more of a hope this helps others post.

I have found that I have needed to create a map of type Map<Id, Opportunity> in many triggers, so I decided to create a small method to genericize this type of behavior.   I'm sure this method can be genericized further so that it can create a map of any SObject, not just opportunity, but I just don't have the time to do that =)

Hope this helps others.  Would also gladly accept feedback on ways to improve the code as I'm not really a seasoned apex developer:

    /**
     * @description Return an opportunityMap for objects that
     * 				have a lookup or parent-child relationship to opportunity
     * @param sObjects the list of sObjects that have opportunity id
     * @param oppFieldName the field name that has the opportunity id
     * @param oppSelectFields the list of opportunity fields to select
     */
    public static Map<Id, Opportunity> generateOppMap(List<SObject> sObjects, 
    		String oppFieldName, String[] oppSelectFields) {
    			
    	Set<Id> opportunityIds = new Set<Id>();
    	for (SObject so : sObjects) {
    		if (so.get(oppFieldName) != null) {
    			opportunityIds.add((Id) so.get(oppFieldName));
    		}
    	}
    	
    	// Prepare the select string
    	String selectString;
    	for (String oppField : oppSelectFields) {
    		oppField = oppField.trim();
    		if (selectString == null) {
    			selectString = String.escapeSingleQuotes(oppField);
    		} else {
    			selectString += ',' + String.escapeSingleQuotes(oppField);
    		}
    	}
    	String query = 'SELECT ' + selectString + ' FROM Opportunity ' +
    			'WHERE Id in :opportunityIds';
    	
    	Opportunity singleOpp;
    	Opportunity[] opps;
    	if (opportunityIds.size() == 1) {
    		singleOpp = Database.query(query);
    	} else {
    		opps = Database.query(query);
    	}
    	
    	if (opps == null) {
    		opps = new List<Opportunity>();
    		opps.add(singleOpp);
    	}
    	
    	Map<Id, Opportunity> oppMap = new Map<Id, Opportunity>();
    	for (Opportunity opp : opps) {
    		oppMap.put(opp.Id, opp);
    	}
    	
    	return oppMap;

    }