People often try to cram too much information onto a network topology drawing, which results in cluttered diagrams that are difficult to follow. While it is commendable to want to convey every detail of a network's architecture, these details can be arranged in two categories: things that go on a topology drawing, and things that go on a spreadsheet. The difference between the two can be determined by keeping in mind the purpose of a topology drawing, which is simply to convey how packets flow across a network. Details which aren't needed to support this function belong on a spreadsheet or in some similar database.
Below are my personal recommendations regarding what goes where. Your own approach might differ somewhat but these rules have worked well for me.
Device ID. This is usually a hostname. Leave off any domain suffixes. Avoid generic labels like "gateway router" or "firewall."
Link prefixes. Routed links are typically labeled with their respective IP subnets. Depending on the scope of the drawing, it may also be desirable to label device interface addresses.
VLANs. Layer two trunks might be labeled with the VLANs they carry, if appropriate.
Interface IDs. Label physical and logical interfaces with their abbreviated forms, e.g. F0/0 instead of FastEthernet0/0 (or Fa0/0 if it is necessary to distinguish between FastEthernet and FDDI interfaces).
Circuit IDs. When depicting a link through a service provider, always include its circuit ID.
Link bandwidth. Bandwidths are typically conveyed by color-coding links with contrasting colors (for example, don't use orange and yellow where they might be confused). Avoid explicitly labeling the bandwidth of links except where particularly of interest (for example, WAN circuits).
Device ID. This should exactly match what's on the drawing. May include domain suffix (preferably in a separate column for easier readability).
Management IP address. This should be a loopback or other virtual interface that will remain reachable so long as there is at least one functional path to the device. (If you haven't designated management addresses for all of your devices, fix that first, then come back to the drawing.)
Serial number. Necessary for accounting and inventory purposes.
Make and model. Manufacturer and model number, e.g. Cisco 1841.
Software version. E.g. Cisco IOS 12.4(25)T.
Miscellaneous. Installed modules, deployment date, notes, etc.
You might also opt to include a spreadsheet containing per-link details. This should be a sheet or table separate from your device spreadsheet. It should include all the relevant details from the topology drawing (IP prefixes, device and interface IDs, bandwidth) plus whatever additional information you care to add.