My original plan was to do tower of London (as early as possible as recommended here) Monday morning. However, my 2 traveling companions want to catch a match and Wimbledon and Monday looks like our best chance. The only other free day on our itinerary is a Friday and a Saturday. I have heard that The City portion of London was a lot less congested on weekends, but to me it is a bit counterintuitive to plan doing a major tourist activity on a weekend. Will it make a huge difference? Any advice? Saturday is also our last day in London.

I was in London in 2004 for Wimbledon. The city seemed crowded all the time irrespective of the day of the week. We did the Tower "Key Ceremony" in the evening - you do have to obtain tickets ahead of time-but it was a fun experience. One tip for Wimbledon--if you do "the queue" - once you're inside - immediately get in line for a court. We made the mistake of getting food and looking around while others were getting in line for the courts; so we then waited all over again. They don't let you hold seats in a court (unless you have tickets for Center Court or Court 1); so if you leave your seat to go get food-you get back in line and wait to get in again for a new seat.

its busy every day of the week.just make sure you go early in the morning.the queue grows exponentially with time.it was around 20min for me & we got there before it opened.by the time we left the castle the queu was so long we were sure we would not have bothered to wait.

In summer it won't make any difference what day of the week you go; just be there when they open. You know to get your tickets in advance, right?

I did not know to get tickets in advance to the Tower! Should I obtain those online?

Hi-Unless something has changed we bought our Tower tickets for a day visit at the Tower on the day we went.

In person
Tickets can be purchased on the day or in advance from the Tower ticket office or up to seven days in advance from any London Underground station.

You don't have to buy them in advance, but it saves a lot of time standing in line. You can by them online with several weeks' leadtime for mailing; the official website is here:
http://www.hrp.org.uk/
You specify a one-week "window" for the tickets, not a particular day. There are no reservations as such.

You can also buy them at various Tube stops (Tower Hill is one), but sometimes there are lines there just before opening time.

I was happy with our choice to buy them online because we avoided all lines that way. But it looks like others did fine with buying them there. Your call.

Can the Tower tickets purchased in advance from underground stations or the ticket office be used any day, or must you choose a day before purchase?

The advance tickets jbass mentioned were for the night time Keys Ceremony. You have to write for those in advance. They are free - but limited.

For just visiting the Tower, buy your tix at a tube station